Therefore let all the house of Israel know assuredly that God hath made that same Jesus, whom ye have crucified, both Lord and Christ. Peter makes it clear in no uncertain terms that Jesus is LORD by God Almighty's decree. It is a great comfort for Christians to know that He is Lord regardless of what men say or think. Further, it is a comfort to know that we have placed our hand in that sovereign nail-pierced hand to lead us through sorrow, sickness and death. It is a strange salvation that knows nothing about daily submission to Christ the Lord.
Lordship implies willing service.
He was a willing servant. Lordship implies obedience. Lordship implies ownership. He owns me lock, stock and barrel. When sinners bow to His Lordship they not only get saved but their pocketbook gets saved also.