Jesus is faithful  -  2 Timothy 2:13

If we believe not, yet he abideth faithful: he cannot deny himself.

This verse includes all individuals, both believers and unbelievers. Whether it is believed or not, God is faithful. When the Scriptures speak of the faithfulness of God, it generally means that He will always do what is consistent with His character and cannot do and will not do anything that is inconsistent with it.