'Faithfulness' in the Bible

“Woe to you, scribes and Pharisees, hypocrites! For you tithe mint and dill and cummin, and have neglected the weightier provisions of the law: justice and mercy and faithfulness; but these are the things you should have done without neglecting the others.

What then? If some did not believe, their unbelief will not nullify the faithfulness of God, will it?

But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness,