New Revised Standard Version
For if those who are nothing think they are something, they deceive themselves.

Contemporary English Version
If you think you are better than others, when you really aren't, you are wrong.

New American Bible
For if anyone thinks he is something when he is nothing, he is deluding himself.

Douay-Rheims Bible
For if any man think himself to be some thing, whereas he is nothing, he deceiveth himself.

For if any man think himself to be some thing, whereas he is nothing, he deceiveth himself.

if.

Galatians 2:6 But of them who seemed to be some thing, (what they were some time it is nothing to me, God accepteth not the person of man): for to me they that seemed to be some thing added nothing.

Proverbs 25:14 As clouds, and wind, when no rain followeth, so is the man that boasteth, and doth not fulfil his promises.

Proverbs 26:12 Hast thou seen a man wise in his own conceit? there shall be more hope of a fool than of him.

Luke 18:11 The Pharisee standing, prayed thus with himself: O God, I give thee thanks that I am not as the rest of men, extortioners, unjust, adulterers, as also is this publican.

Romans 12:3,16 For I say, by the grace that is given me, to all that are among you, not to be more wise than it behoveth to be wise, but to be wise unto sobriety and according as God hath divided to every one the measure of faith. . . .

1 Corinthians 3:18 Let no man deceive himself. If any man among you seem to be wise in this world, let him become a fool, that he may be wise.

1 Corinthians 8:2 And if any man think that he knoweth any thing, he hath not yet known as he ought to know.

when.

1 Corinthians 13:2 And if I should have prophecy and should know all mysteries and all knowledge, and if I should have all faith, so that I could remove mountains, and have not charity, I am nothing.

2 Corinthians 3:5 Not that we are sufficient to think any thing of ourselves, as of ourselves: but our sufficiency is from God.

2 Corinthians 12:11 I am become foolish. You have compelled me: for I ought to have been commended by you. For I have no way come short of them that are above measure apostles, although I be nothing.

he deceiveth.

1 Corinthians 3:18 Let no man deceive himself. If any man among you seem to be wise in this world, let him become a fool, that he may be wise.

2 Timothy 3:13 But evil men and seducers shall grow worse and worse: erring, and driving into error,

James 1:22,26 But be ye doers of the word and not hearers only, deceiving your own selves. . . .

1 John 1:8 If we say that we have no sin, we deceive ourselves and the truth is not in us.