Judges 13:19,20

And offered it upon a rock The presence and command of the angel being a sufficient warrant for the offering of sacrifice by a person who was no priest, and in a place otherwise forbidden. Vitringa, however, supposes that “it was the angel who upon this occasion performed the principal functions of the priest; the most essential of which was to put the fire to the burnt-offering.” Manoah, he observes, “dared not to perform the offices of the priesthood in the presence of a personage whom he took for an extra-ordinary prophet, commissioned from God. All that he did was done by order of the angel, or as his minister; just as the Israelites obeyed Elijah afterward,” 1 Kings 18:34. The angel, or rather he, (for there is nothing for angel in the original,) did wondrously Bringing fire out of the rock, as in the case of Gideon, Judges 6:21, to consume the burnt-offering, and then ascending in the midst of the flame, hereby manifesting his nature and essence to be spiritual. Off the altar That is, from that part of the rock which served instead of an altar, upon which the sacrifice was laid. Manoah and his wife fell on their faces Partly out of reverence for so glorious a person manifested in so wonderful a manner, and partly out of a religious horror and fear of death; for the prevention whereof they fell down in the way of supplication to God.