“But avoid foolish questions, and genealogies, and contentions, and strivings about the law; for they are unprofitable and vain.”
King James Version (KJV)
3:8 Be careful to excel in good works - Though the apostle does not lay these for the foundation, yet he brings them in at their proper place, and then mentions them, not slightly, but as affairs of great importance. He desires that all believers should be careful - Have their thoughts upon them: use their best contrivance, their utmost endeavours, not barely to practise, but to excel, to be eminent and distinguished in them: because, though they are not the ground of our reconciliation with God, yet they are amiable and honourable to the Christian profession. And profitable to men - Means of increasing the everlasting happiness both of ourselves and others.
3:10 An heretic (after a first and second admonition) reject - Avoid, leave to himself. This is the only place, in the whole scripture, where this word heretic occurs; and here it evidently means, a man that obstinately persists in contending about foolish questions, and thereby occasions strife and animosities, schisms and parties in the church. This, and this alone, is an heretic in the scripture sense; and his punishment likewise is here fixed. Shun, avoid him, leave him to himself. As for the Popish sense, A man that errs in fundamentals, although it crept, with many other things, early into the church, yet it has no shadow of foundation either in the Old or New Testament.
3:11 Such an one is perverted - In his heart, at least. And sinneth, being self - condemned - Being convinced in his own conscience that he acts wrong.
Tit 3:9 But avoid foolish questions. How often this admonition! And genealogies. See PNT "1Ti 1:4". And strivings about the law. Disputes over points connected with the Jewish law.