2 Timothy 2v11
The saying is trustworthy, for: If we have died with him, we will also live with him; 12 if we endure, we will also reign with him; if we deny him, he also will deny us; 13 if we are faithless, he remains faithful for he cannot deny himself.

Even when we lose faith He is still faithful to us because He can not deny Himself who is in us. That is a loving God. That is grace. That is a reason for even more faith.