And YHVH God took the man, and put him in the garden of Eden to dress it and to keep it. Gen 2:15
The primitive root
Strong’s H8104 שמר shamar, a primitive root, “to keep, to watch, to guard as a husbandman or shepherd.” The modern three-letter root is shin + mem + resh. The Ancient Hebrew Lexicon tells us that the shin + mem in this root were originally a sin + nun, the similar sounds becoming transposed over time. So the ancient pictographs were sin + nun + resh.
sin ס = the thorn, thus grab, hate, protect
nun נ = the seed, thus continue, heir, son
resh ר = the head of man, thus head, first, top, beginning, man
Shepherds would surround their flocks at night with thorn branches to protect them from predators when they were pasturing them away from the fold. They kept or guarded their flocks so that their children would be provided for. Thus, to closely guard (sin) for the next generation (nun) that which is of first importance (resh).