2 Samuel 3:13

And he said, well, I will make a league with thee
He accepted of the offer, he was ready and willing to enter into a covenant of friendship with him, and forgive all past offences:

but one thing I require of thee;
as the condition of this covenant:

that is, thou shall not see my face;
be admitted into my presence, or have any mark of my favour and respect:

except thou first bring Michal, Saul's daughter, when thou comest to
see my face;
he insisted on it that Michal, Saul's daughter, and his wife, should be brought along with him, and presented to him; this was the preliminary to the league and covenant; if this was not complied with, the proposal would not be attended to. This shows the great affection David retained for his first wife, though he had had six since, see ( 2 Samuel 3:2-5 ) , and though she had lived with another man, ( 1 Samuel 25:44 ) ; as also his great regard to the honour of Saul's family, that one of them might share with him in the grandeur of the kingdom; though this also might be a piece of policy in him, to gain the friends of Saul's family to him.