Here are 4 Bible verses about seraphim from the Old and New Testaments of the Holy Bible (King James Version), sorted from most to least relevant.
Isaiah 6:6-7 KJV
Then flew one of the seraphims unto me, having a live coal in his hand, which he had taken with the tongs from off the altar: And he laid it upon my mouth, and said, Lo, this hath touched thy lips; and thine iniquity is taken away, and thy sin purged.
Isaiah 6:3 KJV
And one cried unto another, and said, Holy, holy, holy, is the LORD of hosts: the whole earth is full of his glory.
Revelation 4:8 KJV
And the four beasts had each of them six wings about him; and they were full of eyes within: and they rest not day and night, saying, Holy, holy, holy, Lord God Almighty, which was, and is, and is to come.
Isaiah 6:2 KJV
Above it stood the seraphims: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly.