Forget: put out of one's mind; cease to think of or consider; fail to remember; inadvertently neglect to attend to; fail to remember; to treat with inattention or disregard.
Forget can be a pretty harsh word. To cease to think of or consider? Ouch. Forgetting is usually an accident, but when we forget something important, it can seem as if we don't remember because we don't care.
Engraved: to be permanently fixed in; to impress deeply.
Engraving seems pretty permanent to me. There's no easy way to undo it, if there is a way at all.
Palm: the inner surface of the hand between the wrist and fingers.
The part of your hand that does a lot of touching. The part of your hand that you feel with.
"Can a mother forget the baby at her breast and have no compassion on the child she has borne? Though she may forget, I will not forget you! See, I have engraved you on the palms of my hands."
Isaiah 49:15-16