Augustine of Hippo

(de Con. Ev. ut sup.) We may understand that one Angel was seen by the women, as both Mark and Matthew say, so as supposing them to have entered into the sepulchre, that is, into a certain space which was fenced off by a kind of wall in front of the stone sepulchre; and that there they saw an Angel sitting on the right hand, which Mark says, but that afterwards when they looked into the place where our Lord was lying, they saw within two other Angels standing, (as Luke says,) who spoke to encourage their minds, and build up their faith. Hence it follows, And as they were afraid.