Note 26 at 2 Tim. 2:13: In the previous verse, Paul gave a stern warning to anyone who willfully and maliciously denies the Lord. He wasn't speaking of a simple failure on our part. He was speaking of total rejection of the Lord. This isn't saying that weak Christians will be denied by the Lord. This is speaking of the apostate who spitefully resists the Lord. This verse confirms that point.

When we fail to believe as we should, God is faithful to Himself. He has sworn that He will never leave us nor forsake us (Heb. 13:5), and He won't. He will not be the one to divorce us, regardless of how unfaithful we are. We have to initiate the proceedings and divorce Him.

It's like a car that loses its forward momentum. The speed may decrease or the vehicle could even stand still, but it has still moved beyond its original position. However, if the car is put in reverse and accelerated, it will eventually go beyond its starting position.

Likewise, Christians who simply slow down or fail to move forward are not in danger of the Lord denying them. But those who go in the other direction and continue to do so until they become hardened and willfully reject the Lord are reprobates (see note 6 at Rom. 1:28, p. 746).

Note 27 at 2 Tim. 2:13: The NIV translates this verse as, "If we are faithless, he will remain faithful, for he cannot disown himself." Our covenant of salvation was not made between God and us directly. It was made between God the Father and our Lord Jesus Christ (see note 5 at Gal. 3:20, p. 1069). We simply accessed their covenant through faith. We are participating in their covenant that they made between Themselves.

If we fail to believe, the covenant still holds because of the oath the Father made to His Son. Otherwise, it would be like God denying Himself. We have to do more than not believe to get out of this covenant. We have to disbelieve or deny God before He will deny us (see note 25 at v. 12).