In this painting, Juan Antonio de Frías y Escalante (1633-1669) shows an angel coming to Elijah, a story related in I Kings 19:4-8:
...he himself went a day's journey into the wilderness, and came and sat down under a juniper tree: and he requested for himself that he might die; and said, It is enough; now, O LORD, take away my life; for I am not better than my fathers.
And as he lay and slept under a juniper tree, behold, then an angel touched him, and said unto him, Arise and eat.
And he looked, and, behold, there was a cake baken on the coals, and a cruse of water at his head. And he did eat and drink, and laid him down again.
And the angel of the LORD came again the second time, and touched him, and said, Arise and eat; because the journey is too great for thee.
And he arose, and did eat and drink, and went in the strength of that meat forty days and forty nights unto Horeb the mount of God.