Hamlet is agreeing that the final will is the will of God.
Explanation:
Hamlet is a very indecisive character in the play and his philosophical discussions with himself and his rhetorical dilemmas form the appeal of the play.
Here, in this frantic statement he is arguing to himself, or consoling himself that the divinity is the one that shapes the ends of the people.
He means that there is no way for humans to change their fate or even modify it as they wish because God has written for them in a way that cannot be altered with.
He is agreeing to the superiority of predestination over free will.
