'Serve' in the Bible

For your servant vowed a vow while I stayed at Geshur in Syria, saying, 'If Yahweh shall indeed bring me again to Jerusalem, then I will serve Yahweh.'"

Again, whom should I serve? Shouldn't I serve in the presence of his son? As I have served in your father's presence, so will I be in your presence."

You also have delivered me from the strivings of my people. You have kept me to be the head of the nations. A people whom I have not known will serve me.