'Faithful Witness' in the Bible

It will be established forever like the moon, the faithful witness in the sky." Selah.

and I will take for myself faithful witnesses to testify: Uriah the priest, and Zechariah the son of Jeberechiah."

Then they said to Jeremiah, Yahweh be a true and faithful witness among us, if we don't do according to all the word with which Yahweh your God shall send you to us.

and from Jesus Christ, the faithful witness, the firstborn of the dead, and the ruler of the kings of the earth. To him who loves us, and washed us from our sins by his blood;