'Entered' in the Bible

When they entered the land of Zuph, Saul said to his servant who [was] with him, "Come, let us return, lest my father cease [caring about] the female donkeys and worry about us!"

So David came to Saul and {entered his service}. He loved him greatly and {he became Saul's armor bearer}.

Then David said to Achish, "But what have I done? And what have you found in your servant from the day that I {entered your service} until this day, that I should not go and fight against the enemies of my lord the king?"