Song of Solomon 8:6 in the King James Version
Set me as a seal upon thine heart, as a seal upon thine arm: for love is strong as death; jealousy is cruel as the grave: the coals thereof are coals of fire, which hath a most vehement flame.
Context
5 Who is this who comes up from the wilderness, leaning on her beloved? Beloved Under the apple tree I awakened you. There your mother conceived you. There she was in labor and bore you.
6 Set me as a seal on your heart, as a seal on your arm; for love is strong as death. Jealousy is as cruel as Sheol. Its flashes are flashes of fire, a very flame of the LORD.
7 Many waters can’t quench love, neither can floods drown it. If a man would give all the wealth of his house for love, he would be utterly scorned.