'Servant' in the Bible

From: Paul, a servant of Jesus the Messiah, called to be an apostle and set apart for God's gospel,

Who are you to criticize someone else's servant? He stands or falls before his own Lord and stand he will, because the Lord makes him stand.

For I tell you that the Messiah became a servant of the circumcised on behalf of God's truth in order to confirm the promises given to our ancestors,