A.T. Robertson Commentary Revelation 1:14

"And his head and his hair were white as white wool, [white] as snow; and his eyes were as a flame of fire;" — Revelation 1:14 (ASV)

As white wool (ως εριον λευκον). Εριον (wool) in N.T. only here and Heb 9:19, though old word. The person of the Lord Jesus is here described in language largely from Da 7:9 (the Ancient of Days).

White as snow (ως χιων). Just "as snow," also in Da 7:9. In N.T. only here and Mt 28:3.

As a flame of fire (ως φλοξ πυρος). In Da 7:9 the throne of the Ancient of Days is φλοξ πυρος, while in Da 10:6 the eyes of the Ancient of Days are λαμπαδες πυρος (lamps of fire). See also 2:18; 19:12 for this bold metaphor .