Zadok the priest
A priest in King David and King Solomon's courts. (2 Samuel 8:17, 2 Samuel 20:25; 1 Kings 4:4) Priest Abiathar was deposed by Solomon in favor of him (1 Kings 1:26-27,35) in accordance with Yahweh's denunciation of Eli's family. (1 Samuel 2:27-36)
(The ESV Study BibleTM, English Standard Version (ESV) by Crossway Bibles, 2007. Page 1369)
His Life
Abiathar, Zadok, and the Levites bring the ark to David as he flees Absalom, but David has them stay in the city to be his eyes and ears
When King David was fleeing Absalom, Abiathar and Zadok came to him with all the Levites, bearing the ark of the covenant. They set down the ark until the people had all passed out of the city. King David told Zadok, "Are you not a seer? Go back to the city in peace, with your two sons, Ahimaaz your son, and Jonathan the son of Abiathar. See, I will wait at the fords of the wilderness until word comes from you to inform me." So Zadok and Abiathar carried the ark to Jerusalem and remained there. (2 Samuel 15:24-29)
Hushai sends word to David to flee Absalom
Hushai came to Zadok and Abiathar with a message for David: Ahithophel advised Absalom to let him take out only David with 12000 chosen men and to capture the rest, while Hushai advised for Absalom to personally lead all Israel to take out David and his men. Absalom and all the elders of Israel found Hushai's counsel better. Therefore, he wanted David to know, "Do not stay tonight at the fords of the wilderness, but by all means pass over, lest the king and all the people who are with him be swallowed up."
Jonathan and Ahimaaz waited at En-rogel, for they were not to be seen entering the city. A female servant was sent to tell them, and they got the message to David.
David sways the hearts of Judah through Zadok and Abiathar, and he replaces Joab with Amasa as commander
David told Zadok and Abiathar to tell the elders of Judah, "Why should you be the last to bring the king back to his house, when the word of all Israel has come to the king? You are my brothers; you are my bone and my flesh. Why then should you be the last to bring back the king?" and to Amasa, "Are you not my bone and my flesh? God do so to me and more also, if you are not commander of my army from now on in place of Joab." Judah sent word to the king, “Return, both you and all your servants.”
Zadok the priest did not support Adonijah when he was exalting himself, saying "I will be king," during King David's old age. Neither did Benaiah the son of Jehoiada, Nathan the prophet, Shimei, Rei, or David's mighty men.
After Bathsheba and Nathan the prophet told King David about Adonijah's exaltation, he called Zadok the priest, Nathan the prophet, and Benaiah to himself to instruct them to anoint Solomon as king.
They obeyed. Zadok the priest, Nathan the prophet, Benaiah the son of Jehoiada, the Cherethites, and the Pelethites had Solomon ride on King David's mule on their way to Gihon. Zadok anointed Solomon with a horn of oil. Then they blew the trumpet and said, "Long live King Solomon!" All the people went up after him, playing on pipes, and rejoicing with great joy, "so that the earth was split by their noise."
Unsorted
King Solomon put Zadok the priest in Abiathar's place. (1 Kings 2:35)
Zadok the son of Azor
The son of Azor and the father of Achim. He was in the line of Christ through Joseph. (Matthew 1:14)