The angel of the Lord. Literally, "an angel of Jehovah." Taking the whole narrative altogether, we are justified in concluding that the appearance was that of "the Angel of the Covenant" or" the Second Person of the Trinity himself;" but this is not stated nor implied in the present verse.
We learn it from what follows. The angel "appeared in a flame of fire out of the midst of the thorn-bush"—not out of "a thorn-bush—which may be explained by there being only one on the spot, which however seems improbable, as it is a common tree; or by Moses having so often spoken of it, that, when he came to write to his countrymen, he naturally called it "the bush," meaning "the bush of which you have all heard."
So St. John says of the Baptist (John 3:24) that "he was not yet cast into the prison, meaning, prison into which you all know that he was cast. Seneh, the word translated "bush," is still the name of a thorny shrub, a species of acacia, common in the Sinaitic district.