John Wesley on Genesis 49:19

Concerning Gad, he alludes to his name, which signifies a troop, foresees the character of that tribe, that it should be a warlike tribe; and so we find, 1Ch 12:8, the Gadites were men of war fit for the battle. He foresees, that the situation of that tribe on the other side Jordan would expose it to the incursions of its neighbours, the Moabites and Ammonites; and that they might not be proud of their strength and valour, he foretells that the troops of their enemies should, in many skirmishes, overcome them; yet, that they might not be discouraged by their defeats, he assures them, that they should overcome at the last, which was fulfilled, when in Saul's time and David's the Moabites and Ammonites were wholly subdued.