The first occurrence.
Hereby you shall be proved: By the life of Pharaoh, you shall not go forth from here, except your youngest brother come hither. Gen 42:15
The primitive root.
Strong’s H974 בחן bachan, a primitive root meaning, “to examine.” The 3-letter root is bet + chet + nun.
bet ב = the house, thus house, household, family, in, within
chet ח = the wall, thus outside, divide, half
nun נ, ן = the seed, thus continue, heir, son
The story: The cognate words from this verbal root will help us find the story. One is slaughter, a task always done in relation to the house (bet), outside (chet), for the benefit of the children (nun) with mouths to feed. Another is sacrifice; another is choice, as only the best animals were slaughtered for sacrifice. So we come to examine, as the animal had to be thoroughly vetted in order for it to pass the test of choicest.
Examination, testing, brings out the truth, and allows the true nature to show forth. This is why a witness on the witness stand is cross examined – to show forth the truth of his testimony.