John Gill Commentary 2 Samuel 14:29

"Then Absalom sent for Joab, to send him to the king; but he would not come to him: and he sent again a second time, but he would not come." — 2 Samuel 14:29 (ASV)

Therefore Absalom sent for Joab, to have sent him to the king ,
&c.] To introduce him into his presence, being uneasy to be thus confined at his own house, and not suffered to come to court:

but he would not come to him ;
knowing the king's mind, and being unwilling to disoblige him by a troublesome solicitation:

and when he sent again the second time, he would not come ;
knowing his business with him; and perhaps between the first time of his sending and this he had sounded the king about it, and found it was not agreeable to him to admit him to access to him as yet.