'Steadfast' in the Bible

“O Lord God, do not turn away and reject the face of Your anointed; remember Your lovingkindness and faithfulness to Your servant David.”

So they got up early in the morning and went out into the Wilderness of Tekoa; and as they went out, Jehoshaphat stood and said, “Hear me, O Judah, and you inhabitants of Jerusalem! Believe and trust in the Lord your God and you will be established (secure). Believe and trust in His prophets and succeed.”