Isaiah 6:2
6:2 Seraphs stood over him; each one had six wings. With two wings they covered their faces, with two they covered their feet, and they used the remaining two to fly.
Daniel 9:21-23
9:21 yes, while I was still praying, the man Gabriel, whom I had seen previously in a vision, was approaching me in my state of extreme weariness, around the time of the evening offering.
9:22 He spoke with me, instructing me as follows: “Daniel, I have now come to impart understanding to you.
9:23 At the beginning of your requests a message went out, and I have come to convey it to you, for you are of great value in God’s sight. Therefore consider the message and understand the vision:
Hebrews 1:7
1:7 And he says of the angels, “He makes his angels spirits and his ministers a flame of fire,”
Hebrews 1:14
1:14 Are they not all ministering spirits, sent out to serve those who will inherit salvation?