Isaiah 23:3

And by great waters the seed of Sihor
Sihor is the river Nile in Egypt; it had its name from the black colour of its waters, as in ( Jeremiah 2:18 ) hence called by the Greeks Melas, and by the Latins Melo: the "seed" of it intends what was sown and grew upon the banks of it, or was nourished by the overflow of this river throughout the land, and includes corn, flax, paper with which Egypt abounded; and when this is said to be "by great waters", the meaning either is, that it grew by great waters, the waters of the Nile, and through the influence of them; or that it came by great waters to Tyre; that is, by the waters of the sea, the Mediterranean Sea:

the harvest of the river [is] her revenue;
this clause is the same with the former, and serves to explain it; the river is the river Nile, the harvest is the seed that was sown and grew by it, and which at the proper season, when ripe, was gathered from it, and carried in ships to Tyre, with which that city was supplied and enriched, as if it had been its own produce:

and she is a mart of nations;
Tyre was a city to which all nations traded, it was a mart for them all, and where they brought their wares to sell, and always found a market for them, here they had vent. The twenty seventh chapter of Ezekiel ( Ezekiel 27:1-13 ) is a proper commentary on this clause.