Tertullian

He revealed to Daniel himself expressly as "the Son of man, coming in the clouds of heaven" as a judge, as also the Scripture shows. What I have advanced might have been sufficient concerning the designation in the prophecy of the Son of man. But the Scripture offers me further information, even in the interpretation of the Lord himself. The Jews, who looked at him as merely man, were not yet sure that he was God also, as being likewise the Son of God. They rightly enough said that a man could not forgive sins, but God alone. Why did he not, following up their point, answer them, that he had power to remit sins, inasmuch as, when he mentioned the Son of man, he also named a human being? Because he wanted, by help of the very designation Son of man from the book of Daniel, so to induce them to reflect as to show them that he who remitted sins was God and man—that only the Son of man, indeed, in the prophecy of Daniel, who had obtained the power of judging, and thereby, of course, of forgiving sins likewise (for he who judges also absolves); so that, when once that objection of theirs was shattered to pieces by their recollection of Scripture, they might the more easily acknowledge him to be the Son of man himself by his actual forgiveness of sins.