'Whom' in the Bible

I thank God, whom I worship and serve with a clear conscience the way my forefathers did, as I constantly remember you in my prayers night and day,

This is why I suffer as I do. Still, I am not ashamed; for I know Him [and I am personally acquainted with Him] whom I have believed [with absolute trust and confidence in Him and in the truth of His deity], and I am persuaded [beyond any doubt] that He is able to guard that which I have entrusted to Him until that day [when I stand before Him].

But as for you, continue in the things that you have learned and of which you are convinced [holding tightly to the truths], knowing from whom you learned them,