It is to fulfill God’s Will for one’s own life (which differs from person to person as our roles are different):

“For it is God which worketh in you both to will and to do of His good pleasure.” (Philippians 2:13)

P/S:

Rebellion is anything against His Will:

“For I the LORD will speak, and whatever word I speak will be performed. It will no longer be delayed, for in your days, O rebellious house, I will speak the word and perform it,” declares the Lord GOD.'” (Ezekiel 12:25)

And, that’s the Crux Requirement to be a man ‘after God’s Own Heart’ (as King David was) which is revealed also in the verse below:

“And having removed him, He raised up David to them as king, to whom also He said, having carried witness: ‘I have found David the son of Jesse a man according to My heart, who will do all My will.'” (Acts 13:22)