Deuteronomy 33:20

Mosheh the prophet of the Lord blessed the tribe of Gad, and said: Blessed be He who hath made wide the border of Gad. He reposeth as a lion in his habitation; but when he goeth out to battle against his adversaries, he slayeth kings and rulers, and his slaughtered ones are known from all the slain, for he striketh off the arm with the crown (of the head).

Who gives Gad space He compares Gad to a lion; everyone who sees him will flee, and no one will crowd him.

BLESSED BE HE THAT ENLARGETH GAD. “This teaches that Gad’s border was enlarged toward the east.” [Since his territory was east of the Jordan it could be extended towards the east.] This is Rashi’s language from the Sifre. 355. And Rabbi Abraham ibn Ezra commented that because Moses likened Gad to a lion [he dwelleth as a lioness], he said, “Blessed be He Who enlarges Gad, Who gives him strength so that whoever [any enemy] sees him will flee him, and no one will trouble him.” The correct interpretation is that it refers to Gad’s inheritance, for the two tribes [Reuben and Gad] that took their inheritance on the east bank of the Jordan did not take it by the lot. Instead Moses gave them the entire kingdoms of Sihon and Og and their inheritance was broader as it wound about higher than all the tribes. Moses did not mention this [blessing] in the case of Reuben, for his prayer was sufficient. It is also possible that the children of Gad took more territory than the children of Reuben for they were mighty and therefore Moses gave them the entire [eastern] border. The cities which they built were also more numerous than those of Reuben., Verses 37-38. In addition, it was the Gadites who first requested that land [east of the Jordan as their inheritance] as I have explained there,, Verse 2 (Vol. IV, pp. 370-371). and thus they were the cause of this expansion.

ברוך מרחיב גד, Who has given him a larger tract of land on the east bank of the Jordan than any other tribe received even in that part of the country. For while it is true that the lands of Sichon and Og were larger in the number of square meters accorded to the tribes on the west bank, the latter were of the category known as “flowing with milk and honey,” whereas the land on the east bank was primarily grazing land as opposed to “homesteading” land, i.e. farming land.

כלביא שכן, he deserves the extra acreage as he holds his own against enemies that surround him and he behaves like a brave courageous lion though badly outnumbered. Such a lion does not hesitate to devour what is around him.

ברוך מרחיב גד, “blessed be he who enlarges the territory of the tribe of Gad.” Seeing that the ancestral land allotted to Gad was suitable for grazing rather than planting crops, this root is more appropriate for describing expansion. Compare also Hoseah 4,16: “עתה ירעם ה' ככבש בשמרחב, “now the Lord will graze him on the range like a sheep.”

וטרף זרוע אף קדקד, “and he tears the arm, as well as the crown of the head.” Rabbi B’chor Shor explains this line when the attacker will strike the victim and he raises his hands in self defense, holding it in front of his face for protection, that attacker will strike him on the head instead. As a result the blow will even injure the shoulder of the victim