New Revised Standard Version
He conferred with Joab son of Zeruiah and with the priest Abiathar, and they supported Adonijah.

Contemporary English Version
Adonijah met with Joab the son of Zeruiah and Abiathar the priest and asked them if they would help him become king. Both of them agreed to help.

New American Bible
He consulted with Joab, son of Zeruiah, and with Abiathar the priest, and they became Adonijah’s supporters.

Douay-Rheims Bible
And he conferred with Joab, the son of Sarvia, and with Abiathar, the priest, who furthered Adonias's side.

And he conferred with Joab, the son of Sarvia, and with Abiathar, the priest, who furthered Adonias's side.

And he conferred [heb] his words were

2 Samuel 15:12 Absalom also sent for Achitophel the Gilonite, David's counsellor, from his city Gilo. And while he was offering sacrifices, there was a strong conspiracy, and the people running together increased with Absalom.

Psalm 2:2 The kings of the earth stood up, and the princes met together, against the Lord, and against his Christ.

Joab

1 Kings 2:28 And the news came to Joab, because Joab had turned after Adonias, and had not turned after Solomon: and Joab fled into the tabernacle of the Lord, and took hold on the horn of the altar.

2 Samuel 8:16 And Joab the son Sarvia was over the army: and Josaphat the son of Ahilud was recorder:

2 Samuel 20:23 So Joab was over all the army of Israel: and Banaias the son of Joiada was over the Cerethites and Phelethites,

Abiathar

1 Samuel 22:20-23 But one of the sons of Achimelech, the son of Achitob, whose name was Abiathar, escaped, and fled to David, . . .

2 Samuel 15:24-29,35 And Sadoc the priest also came, and all the Levites with him carrying the ark of the covenant of God, and they set down the ark of God: and Abiathar went up, till all the people that was come out of the city had done passing. . . .

2 Samuel 20:25 And Siva was scribe: and Sadoc and Abiathar, priests.

1 Kings 2:22,26-35 And king Solomon answered, and said to his mother: Why dost thou ask Abisag, the Sunamitess, for Adonias? ask for him also the kingdom; for he is my elder brother, and hath Abiathar, the priest, and Joab, the son of Sarvia. . . .