Deuteronomy 33:19

Mountain. Full of gratitude to God, who has bestowed such advantages upon them, these tribes shall go with zeal to the place which the Lord shall choose, (Haydock) and invite the people, on the road, to go along with them, to offer sacrifice. (Menochius)

Perhaps this may allude also to their conduct in the war against Jabin, in which they were particularly active, appointing the place of rendezvous at Mount Thabor, where, though the Scripture be silent, it is probable they would offer a sacrifice of thanks, as they had the prophetess, Debora, along with them, (Calmet) in like manner as Samuel immolated a calf at Bethlehem, (1 Kings xvi.) and Elias a bullock on Mount Carmel, 3 Kings xviii. (Haydock) See 1 Kings xiii. 12.

Sands. This blessing chiefly regarded Zabulon, who received the riches of the sea by commerce, bringing home the gold dust which is found among the sand of some rivers. The river Belus, near Ptolemais, was particularly famous for a sort of sand, of which glass was made. Josephus (Jewish Wars ii. 17,) says, that near the tomb of Memnon, a bed of such sand is found, about 100 cubits long, which, though many vessels have been filled from it, has never been exhausted. See Pliny, [Natural History?] v. 19., and Strabo, xvi.

The discovery of glass is supposed to have been the effect of chance; some merchants having placed a nitrous stone under their pot, as soon as it grew hot, and mixed with the sand, which is found near the shore of Tyre, a transparent substance was formed, which the Greeks called ualos, "glass," perhaps in imitation of the Hebrew éul, or "sand," of which it was chiefly composed. (Calmet)