How about this:
Hermas
"[The Shepherd said:] ‘But those who are weak and slothful in prayer, hesitate to ask anything from the Lord; but the Lord is full of compassion, and gives without fail to all who ask him. But you, [Hermas,] having been strengthened by the holy angel [you saw], and having obtained from him such intercession, and not being slothful, why do not you ask of the Lord understanding, and receive it from him?’" (The Shepherd 3:5:4 [A.D. 80]).
Clement of Alexandria
"In this way is he [the true Christian] always pure for prayer. He also prays in the society of angels, as being already of angelic rank, and he is never out of their holy keeping; and though he pray alone, he has the choir of the saints standing with him [in prayer]" (Miscellanies 7:12 [A.D. 208]).
Origen
"But not the high priest [Christ] alone prays for those who pray sincerely, but also the angels . . . as also the souls of the saints who have already fallen asleep" (Prayer 11 [A.D. 233]).
Hermas
"[The Shepherd said:] ‘But those who are weak and slothful in prayer, hesitate to ask anything from the Lord; but the Lord is full of compassion, and gives without fail to all who ask him. But you, [Hermas,] having been strengthened by the holy angel [you saw], and having obtained from him such intercession, and not being slothful, why do not you ask of the Lord understanding, and receive it from him?’" (The Shepherd 3:5:4 [A.D. 80]).
Clement of Alexandria
"In this way is he [the true Christian] always pure for prayer. He also prays in the society of angels, as being already of angelic rank, and he is never out of their holy keeping; and though he pray alone, he has the choir of the saints standing with him [in prayer]" (Miscellanies 7:12 [A.D. 208]).
Origen
"But not the high priest [Christ] alone prays for those who pray sincerely, but also the angels . . . as also the souls of the saints who have already fallen asleep" (Prayer 11 [A.D. 233]).