And of Gad he said,
Blessed be he who enlarges Gad:
He dwells as a lioness,
And tears the arm, yes, the crown of the head.
And he provides the first part for himself,
For there was the commander's (or ‘lawgiver's) portion reserved;
And he came at the heads of the people;
He executed the righteousness of Yahweh,
And his ordinances with Israel.
God will enlarge Gad and prosper them. They will be a triumphant predator, seizing the arms of the enemy, and tearing their heads, as a lion seizes its prey. By their prominence in leadership they will be looking first after their own interests, and then after the interests of all the tribes, and will be prominent in the confederacy. They will always be among the leaders, and will have a concern for the carrying out of the righteousness of Yahweh, and the bringing about of His ordinances. Compare Genesis 49:19 where Gad also reveals his strength.
It is clear that by this time these traits were especially noticeable in the tribe of Gad. All the tribes would have altered through the years, years firstly of prosperity and then of oppression. Some would have made more use of the first, and may have responded better to the second. Some would even be in parts of the Delta possibly not so much affected by the oppression. Moses would by this time have gathered much about the futures of these tribes from what he had observed about them and their leadership.
There may also be reference to Gad's part in the future conquest, ‘coming at the heads of the peoples' as befitted a warrior tribe, having themselves already first settled in Transjordan with Moses' blessing. Gad was chosen to replace Levi, combining with the Leah tribes in having a major protective position in the advance through the wilderness (Numbers 1:24; Numbers 2:14-15).
The historical presence of Gad in Transjordan is confirmed on the Moabite Stone where Gad is mentioned by Mesha, the king of Moab.