Abner said to David, "Let me arise and go and gather all Israel to my lord the king,
2 Samuel 3:21
No man "let" David become king.
Abner offered David the kingdom of God from his hand, just like Satan offered the Lord Jesus the kingdom of God from his hand, but there can be no "let me" in the kingdom of God.
David would not be king by the hand of Abner but by the hand of God. When David made a covenant with Abner, David did not inquire of God. It was as important to God, how David received the kingdom as that he received the kingdom. He must receive the kingdom from God alone. The Lord Jesus was tempted by Satan to receive all the kingdoms of the world from his hand and bypass the cross. But the kingdoms of this world must be awarded to the Lord Jesus from the hand of God the Father and only to a crucified and risen Son of Man. No man will "let" Jesus rule as King.
When you are sure that a thing is the will of God for you, make more sure that you obtain that thing in the will and timing of God also.
For me to live is Christ.