Albert Barnes Commentary Deuteronomy 33:18-19

"And of Zebulun he said, Rejoice, Zebulun, in thy going out; And, Issachar, in thy tents. They shall call the peoples unto the mountain; There shall they offer sacrifices of righteousness: For they shall suck the abundance of the seas, And the hidden treasures of the sand." — Deuteronomy 33:18-19 (ASV)

Zebulun possessed a spacious sea-shore and the fisheries of the Lake of Tiberias. Therefore, he was to thrive by commerce and to rejoice in his going out, that is, in his commercial ventures. Issachar possessed a fertile inland district and would therefore dwell at home and prosper in agriculture. Both tribes distinguished themselves in the contest with Jabin (Compare to Judges 5:14-15, 18). Of Zebulun, it is particularly noted that it produced the officers and tacticians who led and marshalled the army that defeated Sisera (see Judges 5:14, and compare to 1 Chronicles 12:33).

Unto the mountain (Deuteronomy 33:19) — Compare Exodus 15:17.

Sacrifices of righteousness (Deuteronomy 33:19) — Sacrifices offered in a righteous spirit, and therefore well pleasing to God (Psalms 51:19).

Treasures hid in the sand (Deuteronomy 33:19) — The riches of the seas in general. However, it is noteworthy that the sand of these coasts was especially valuable in the manufacture of glass, and glass was a precious thing in ancient times . The murex, from which the highly-prized purple dye was extracted, was also found here. A typical reference to the conversion of the Gentiles is strongly suggested by Isaiah 60:5-6, Isaiah 60:16, and Isaiah 66:11-12.