genesis 37:26 And Judah said unto his brethren, What profit is it if we slay our brother, and conceal his blood? - Free Bible Online

      26-28. Judah said, . . . What profit is it if we slay our brother?--The sight of these travelling merchants gave a sudden turn to the views of the conspirators; for having no wish to commit a greater degree of crime than was necessary for the accomplishment of their end, they readily approved of Judah's suggestion to dispose of their obnoxious brother as a slave. The proposal, of course, was founded on their knowledge that the Arabian merchants trafficked in slaves; and there is the clearest evidence furnished by the monuments of Egypt that the traders who were in the habit of bringing slaves from the countries through which they passed, found a ready market in the cities of the Nile.
      they . . . lifted up Joseph out of the pit, and sold him--Acting impulsively on Judah's advice, they had their poor victim ready by the time the merchants reached them; and money being no part of their object, they sold him for
      twenty pieces of silver--The money was probably in rings or pieces (shekels), and silver is always mentioned in the records of that early age before gold, on account of its rarity. The whole sum, if in shekel weight, did not exceed £3.
      they brought Joseph into Egypt--There were two routes to Egypt: the one was overland by Hebron, where Jacob dwelt, and by taking which, the fate of his hapless son would likely have reached the paternal ears; the other was directly westward across the country from Dothan to the maritime coast, and in this, the safest and most expeditious way, the merchants carried Joseph to Egypt. Thus did an overruling Providence lead this murderous conclave of brothers, as well as the slave merchants both following their own free courses--to be parties in an act by which He was to work out, in a marvellous manner, the great purposes of His wisdom and goodness towards His ancient Church and people.

JFB.