Hebrews 2:6

but one in a certain place testified The writer was of course perfectly well aware that the Psalm on which he proceeds to comment is the 8th Psalm. This indefinite mode of quotation ("some one, somewhere") is common in Philo and the Rabbis. Scripture is often quoted by the words "It saith" or "He saith" or "God saith. Possibly the indefinite form (comp. Hebrews 4:4) which is not found in St Paul is only here adopted because God is Himself addressed in the Psalm. (See Schöttgen, Nov. Hebr.p. 928.)

What is man The Hebrew word enoshmeans man in his weakness and humiliation. The "what" expresses a double feeling how mean in himself! how great in Thylove! The Psalm is only Messianic in so far as it implies man's final exaltation through Christ's incarnation. It applies, in the first instance, and directly, to man; and only in a secondary sense to Jesus as man. But St Paul had already (1 Corinthians 15:27; Ephesians 1:22) applied it in a Messianic sense, and "Son of man" was a Messianic title (Daniel 7:13). Thus the Cabbalists regarded the name Adam as an anagram for Adam, David, Moses, and regarded the Messiah as combining the dignity of all three. David twice makes the exclamation "What is man?"; once when he is thinking of man's frailty in connection with his exaltation by God (Psalms 8); and once (Psalms 144:3) when he is thinking only of man's emptiness and worthlessness, as being undeserving of God's care, (comp. Job 7:17).