'Sided' in the Bible

Then the king said to the messengers who were stationed beside him, "Turn and kill the priests of the Lord, for they too have sided with David! They knew he was fleeing, but they did not inform me." But the king's servants refused to harm the priests of the Lord.

Now David had been told, "Ahithophel has sided with the conspirators who are with Absalom. So David prayed, "Make the advice of Ahithophel foolish, O Lord!"