Peter calls himself a servant, a slave of Jesus Christ, being owned by Christ. When Christ controls us, we are giving over every area of our life to him.
God will “settle” us, meaning lay a firm foundation for us when we live in obedience to what He says to us in His Word. When we disobey what God is telling us, we weaken the foundation.
Being strengthened by God begins with commitment, turning yourself over. Have faith to allow God’s power to give you help to never to grow tired or wear out.