Barnes New Testament Notes

Verse 19. Holding faith. Fidelity to the cause in which you are enlisted as a good soldier should do. This does not mean, as it seems to me, that Timothy should hold to the system of doctrines revealed in the gospel, but that he should have that fidelity which a good soldier ought to have. He should not betray his trust. He should adhere to the cause of his Master with unwavering steadfastness. This would include, of course, a belief of the truth, but this is not the leading idea in the phrase.

And a good conscience. See Barnes "Ac 23:1".

A good conscience, as well as fidelity, is necessary in the service of the Redeemer. A good conscience is that which is well informed in regard to what is right, and where its dictates are honestly followed.

Which some having put away. That is, which good conscience some have put from them, or in other words, have not followed its dictates The truth thus taught is, that men make shipwreck of their faith by not keeping a good conscience. They love sin. They follow the leadings of passion. They choose to indulge in carnal propensities. As a matter of course, they must, if they will do this, reject and renounce the gospel. Men become infidels because they wish to indulge in sin. No man can be a sensualist, and yet love that gospel which enjoins purity of life. If men would keep a good conscience, the way to a steady belief in the gospel would be easy. If men will not, they must expect sooner or later to be landed in infidelity.

Concerning faith. In respect to the whole subject of faith. They are unfaithful to God, and they reject the whole system of the gospel. "Faith" is sometimes used to denote the gospel -- as faith is the principal thing in the gospel.

Have made shipwreck. There is an entire destruction of faith -- as a ship is wholly ruined that strikes on a rock and sinks.

{b} "Holding faith". "1 Ti 3:9