The first occurrence.
And Cain said unto YHVH, My punishment is greater than I can bear. Gen 4:13
The primitive root.
Strong’s H5375 נשא nasa, “to take up, to lift up, to pardon.” As per the Ancient Hebrew Lexicon, the shin was transposed from an original sin.
nun נ ן = seed, thus continue, heir, son
sin ס = thorn, thus grab, hate, protect
aleph א = ox head, thus strength, power, leader
The story: Persistently (continually, nun) grabbing hold (sin) with strength (aleph), thus labor, to take up or lift up a burden.