Adam Clarke on 2 Timothy 1:3

Whom I serve from my forefathers - Being born a Jew, I was carefully educated in the knowledge of the true God, and the proper manner of worshipping him.

With pure conscience - Ever aiming to please him, even in the time when through ignorance I persecuted the Church.

Without ceasing I have remembrance of thee - The apostle thanks God that he has constant remembrance of Timothy in his prayers. It is a very rare thing now in the Christian Church, that a man particularly thanks God that he is enabled to pray for Others. And yet he that can do this most must have an increase of that brotherly love which the second greatest commandment of God requires: Thou shalt love thy neighbor as thyself. It is also a great blessing to be able to maintain the spirit of a pure friendship, especially through a considerable lapse of time and absence. He that can do so may well thank God that he is saved from that fickleness and unsteadiness of mind which are the bane of friendships, and the reproach of many once warm-hearted friends.