Deuteronomy 33:20

And of Gad he said, Blessed be he that enlargeth Gad: he dwelleth as a lion, and teareth the arm with the crown of the head.

Of Gad he said, Blessed be he that enlargeth Gad - either extends the borders of his territories, of which there was no need, as they were already ample enough; or rather, delivers him from the troubles in which he would be often involved from the attacks of the hostile tribes by which he was encompassed. The word rendered 'enlarge' bears this sense (Psalms 4:1: cf. Psalms 31:8). An instance of the annoyance occasioned to the pastoral tribes east of the Jordan by the surrounding Bedouins is given in Judges 11:1.

He dwelleth as a lion, х shaakeen (H7931)] - couches, rests secure and fearless, though surrounded by enemies. In his forest regions, south of the Jabbok (Zerka), 'he dwelt as a lion' (cf. Genesis 30:2; Genesis 49:19). Gad was a very warlike tribe, and was distinguished for intrepid valour.

And teareth the arm with the crown of the head. [The Septuagint has: suntripsas brachiona kai archonta, crushing the ruler with the power of the enemy.] This is undoubtedly the metaphorical application of the words in this passage. But the phraseology is founded on the habit of the ferocious beasts of prey spoken of in the preceding clause, and which, like all ravenous animals, seize their prey at the shoulder-blade, at a particular point of the neck, near the skull, when a wound in the spinal marrow produces a speedy and apparently a painless death. (See this illustrated by Dr. Livingstone, 'Journal of Travels in Africa.' in his interesting account of his contest with a lion at Mabotsa.)