Verses with the word seraphims in the Old Testament (2 verses):

Isaiah 6:2
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.

Isaiah 6:6
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: