And God blessed the seventh day, and hallowed it; because in it He rested from all His work which God had created and had made. Gen 2:3
Strong’s H6942 קדש qadash, “to be holy.” The first letter is a quph, but according to the Ancient Hebrew Lexicon, the quph was transposed from an original chet, making the ancient pictographs chet + dalet + shin.
chet ח = the wall, thus outside, divide, half
dalet ד = the door, thus enter, move, hang
shin ש = two front teeth, thus sharp, press, eat, two, again
A wall makes a separation (chet) between two parties. When one comes through the wall via its door (dalet), the two parties (shin) can be joined together.