'Faithful' in the Bible

But I will raise up for Myself a faithful priest who will do according to what is in My heart and in My soul; and I will build him an enduring house, and he will walk before My anointed always.

Then Ahimelech answered the king and said, “And who among all your servants is as faithful as David, even the king’s son-in-law, who is captain over your guard, and is honored in your house?