Why say you is, when you ain't?
Why, then, would anyone want to call himself a "Christian" when he
isn't one, when he doesn't embrace the core convictions that
define what it

means to be a Christian? Many reasons are possible. Here are
four:
Wolf-in-sheep's-clothing phenomenon. Particularly in the case of leaders, clergy, or missionaries, if they want to fleece the flock, they won't get in if they appear in their true colors. Sheep One will say, "Dude! Wolf!" — and the sheep will go bleating off. So a cagey leader throws on a few cottony tufts, learns to say "Baa," and stuffs his silverware and A-1 into his pockets.
Social respectability. When a writer from a newspaper interviewed me, as a new pastor in a new town, I mentioned that I had not been raised as a Christian. My dear, late mother was very offended. To her (born 1916), in saying this I implied that I had not had a
moral, civilized upbringing. I meant no such thing, of course; I simply meant I had not been raised in the Biblical, Christian faith.
But Mom represented an America in which to be an American was to be a Christian, which is to say a decent, moral, nominally-religious, vaguely "God"-fearing person. "Unchristian" had no
doctrinal referent; it simply meant crude, rude, uncharitable, ill-bred.
So I think particularly in the case of
politicians, there's enough of a civic memory of this time that it
looks better to be a "Christian" than, say, a Hindu or an atheist. It gets you ten points in the Moral-O-Meter, and provides a nice "cover."

(But only if you're not a
fanatical about it. You can be a Jack Danforth "Christian," a Jimmy Carter "Christian,"a Bill Clinton "Christian,"a Barack Obama "Christian"— certainly not a Sarah Palin Christian.)
Many like to say they're Christians because they
don't really understand the Gospel, but do like perceived benefits. Their notion doesn't include truths and implications such as Luke 9:23, Romans 6 and Hebrews 12. But they like their (mangled) understanding of gauzy themes such as forgiveness, acceptance, eternal hope. Their perversion of it is that they can live like Hell and hope for Heaven, and own a "Get Out Of Guilt Or Accountability" card, if they just say they're Christians. (See under
Clinton, Bill; or, nauseatingly, the
Gutless Grace subset of dispensationalists — who have much to answer for.)
Deeper down, though, lies
suppressed God-consciousness. Paul says quite bluntly, that all men naturally "suppress the truth in unrighteousness" (Romans 1:18). They
know God, but choose not to honor Him as God (v. 21). So at bottom, they know they
should be Christians; they want the
comfort that comes from being a Christian. They like (as I said) the notions of being forgiven, of having hope, of thinking that that whole
death-thingie has been taken care of, and All That. Plus, there's usually no immediate price to pay, in our culture, for
saying you're a Christian. So, just
say it, and all these wonderful prizes and parting-gifts are yours to keep.
So... can you say who is a Christian and who isn't?
Yes, and no.
That isn't nearly as wiggly as it sounds at first glance, so hang in with me.
When the GOP calls itself a "big tent," I always think, "But even the
biggest tent still has
walls." So where are the walls on a political party? I honestly don't know. I know where I think they
should be — but in a party that equally has been home to Ronald Reagan and William Weld, Tom Coburn and Arlen Specter, I just don't know where they are.
At root, though, that is in large measure because the political party has no defining document, no transcendent and objective authority.
This is not the case in Christianity. We have both: the Bible, and the triune God who inerrantly inspired its authorship. (
NOTE: what follows is considered and condensed, not intended for skimming.)
The "yes" part
You'd think a religion called "Christianity" should have something to do with
Christ, wouldn't you? And so, in a sane world, it would.
Christ said: "But why do you call Me 'Lord, Lord,' and do not do the things which I say?" (Luke 6:46 NKJ). Two critical truths at least are highlighted in this dominical bombshell: (1) confession of Jesus' Lordship is foundational; and (2) such a confession must be followed by acceptance of and obedience to His words.
Confession of His Lordship. Jesus Himself put this confession as foundational to the church. Confession that Jesus is Lord, Christ, God incarnate is the foundation-rock on which the church must be built (Matthew 16:16-19; cf. Romans 10:9; 1 Corinthians 3:11). This is the confession that the Holy Spirit inspires (1 Corinthians 12:3b). It is both goal and result of His death on the Cross, and bodily resurrection (Romans 14:9).

Obviously Jesus is Lord in the sense that He is the absolute authority, both supreme teacher and supreme master. Jesus clearly has this in mind in Luke 6:46. But "Lord" is also a common title for Deity throughout the Old Testament — that is, for God. And indeed the Christian confesses Jesus as both his Lord
and his God (John 20:28).
This actually all forms a sort of
endless (but constructive) do-loop. Anywhere you start, you get to the rest of it. That is, if Jesus is God, then He is Lord; if He is Lord, then He is God. How? Jesus affirmed that no less than the Father Himself demanded that the Son receive honor
equal to the honor paid the Father (John 5:23). If He is Lord, then we are to believe what He says; if we believe what He says, then we must believe that He is God.
In either regard, to accept the foundational conviction that Jesus is Lord and God necessarily pays off into...
...acceptance of and obedience to His words. As Lord, Jesus expects me to take His yoke upon myself and
learn of Him (Matthew 11:28-30), and to
do what He tells me (Luke 6:46).
It is not a peer-relationship; the Christian life is not a negotiation. So it follows that, if Jesus is my Lord and my God, I will learn to love what He loves and hate what He hates; to cherish what He values, and spurn what He despises. My convictions and values, and my choices and actions, will be progressively brought into conformity to His.
That is why the NT requires, imposes and provides tests. We see the apostles extending "a
judgment of Christian charity," which is to say that one's profession of faith is accepted,
unless other considerations

make that profession
impossible to accept. Note:
both halves of that statement should receive due weight. The predisposition is to accept a professed brother as such; but equally, disqualifiers do, in fact, disqualify.
Jesus Himself set the stage for this, by depicting
many as falsely expecting to be welcomed to Heaven, when instead they'll be banished to Hell (Matthew 7:21-23).
So, similarly,
Paul says he doesn't care
who preaches a
different Gospel, that person is justly
damned and doomed (Galatians 1:8-9). No honest reader could doubt that Paul's Gospel had definite and distinct form, shape, edges. He lays it out as crucial and foundational, in 1 Corinthians 15:1-11. Paul paints the Gospel as requiring the affirmation and embrace of certain events
and their meanings as assigned by Scripture, including the penal, substitutionary death of Christ, His burial, and His bodily resurrection. In that section as well, Paul stresses the need to cling to this Gospel precisely as given; salvation is to be found nowhere else.
Likewise the apostle
John gives a cycle of
three tests of eternal life (cf. 1 John 5:13). They include correct
doctrine (cf. 4:1-4; 5:1, etc.),
obedience to the written Word of God (2:3-6; 5:2-3, etc.), and
love for the brothers (3:11-18; 4:7-12, etc.). He goes over these three themes, these three tests, again and again, from different angles.
So it isn't surprising that, in contrast to modern "Anything-goes/Whatever" evanjellybeans, we frequently find the Bible referring to
false brothers (2 Corinthians 11:26; Galatians 2:4),
false prophets and
false teachers (2 Peter 2:1), warning against
deceivers (Colossians 2:4, 8, 16-22; Jude 4), and both commanding and commending the exercise of close
discernment (1 Thessalonians 5:21-22; Revelation 2:2). Christians
say they're Christians; but
saying you're a Christian doesn't
make you a Christian.
So yes:
it is possible to trace out the parameters of Christian profession and practice. And it is possible that someone's words and/or life indicate that he
hasn't the right to claim to be a Christian.
The "no" partMany of these tests are meant for me to use on myself, primarily — not (primarily) on others. I am to test myself (2 Corinthians 13:5), and apply John's threefold tests to see if I have eternal life (1 John 5:13). They are not primarily given that I might go around with a big red
C and a big red
P, stamping
Christian or
Phony on anyone I meet.
"Primarily," I say. However, HSAT, I am urged to apply discernment and judgment, as we've seen (cf. Matthew 7:6, etc.). Christian leaders in particular are responsible to identify, deal with, and warn against false teachers and false brothers (cf. Titus 1:10-13; 3:10-11, etc.). The church is to echo this

judgment (cf. Matthew 18:17; 1 Corinthians 5:9-13; 2 Thessalonians 3:6, 14-15).
But I can barely know my own sick, deceptive heart (Jeremiah 17:9), let alone another's (1 Corinthians 2:11). So I must be humble and cautious, must stick with what I can see and hear, must not overreach, and must leave the ultimate decision to God.
Plus we must factor in truths such as Romans 7:14-25, where even the apostle Paul himself said that what he did (and failed to do) was not always right. He did what he shouldn't; he didn't do what he should. His life, unlike Jesus', was not seamlessly perfect and "there" (cf. also Philippians 3:12-13). So even the Christianest Christian we'll ever know will have lapses, failings, weaknesses — sins.
So humility and grace are definitely called for.
However, HSA
T, I not only
can, but
must say that certain words and deeds and concepts and beliefs are
not Biblical,
not Christian,
not pleasing to God — when I have the revealed mind of God on those matters. And I can extrapolate, and warn, rebuke, reprove, exhort. And I can (and
must) warn that a pattern, a path, if not repented of, will lead to Hell.
Though a Christian may sin, he struggles and fights against his sin (Galatians 5:17). He regularly

puts to death the deeds of his body (Romans 8:13). He does not continue in sin (1 John 3:3-4, 8-10). That distinguishes a Christian: he isn't floating downstream towards the waterfall. He fights the current.
And mark this:
there is no sentence, word, nor syllable of Scripture meant to give comfort to anyone willfully continuing in unrepented sin.So: if someone's
confession of "Christ" is heterodox and out of step with Scripture; if his
value-system bears no mark of the yoke of discipleship in the school of Christ; if his
closest associates despise the Lord and His word; and if he
stubbornly resists all attempts to point him to Christ, and to the word of God — then we would be
faithless towards God, and
loveless towards that man or woman, to imagine or hold out any basis to believe him or her to be a Christian.
At the very least, we can and must
certainly say something like,
"What you are saying/doing is offensive to God, and condemned by God. I can't see your heart, but I can see what comes out of your heart. Jesus says that the mouth speaks from what fills the heart (Luke 6:45), and our actions come from our hearts (cf. Proverbs 4:23). These are not the actions nor words of a heart that believes and loves God, and that worries me terribly for you. I implore you, repent, bow the knee to Christ as Lord from your heart — or you have no reason to hope that you have any part in Him or His kingdom."
It's what Jesus would do (Mark 1:15; Luke 13:3, 5; Revelation 3:19).
It's what we should do.