Albert Barnes Commentary 1 Kings 19:5

"And he lay down and slept under a juniper-tree; and, behold, an angel touched him, and said unto him, Arise and eat." — 1 Kings 19:5 (ASV)

An angel touched him - The friendly ministry of angels, which was common during the time of the patriarchs (Genesis 18:2–16; Genesis 19:1–22; Genesis 28:12; Genesis 32:1, 24-29) and also known during the time of the Judges (Judges 6:11–21; Judges 13:3–20), was now extended to Elijah. Any other explanation of this passage violates the plain meaning of the words. It is certainly not the writer's intention to portray Elijah as being helped on this occasion by a human “messenger.”