'Serve' in the Bible

For thy servant vowed a vow while I abode in Geshur in Syria, saying, If Jehovah shall bring me again indeed to Jerusalem, then I will serve Jehovah.

And again, whom should I serve? should it not be in the presence of his son? as I have served in thy father's presence, so will I be in thy presence.

And thou hast delivered me from the strivings of my people, Thou hast kept me to be head of the nations: A people I knew not doth serve me: