Adam Clarke on 2 Kings 15:19

Pul, the king of Assyria - This is the first time we hear of Assyria since the days of Nimrod, its founder, Gen 10:11.

Dean Prideaux supposes that this Pul was father of the famous Sardanapalus, the son himself being called Sardan; to which, as was frequent in those times, the father's name, Pul, was added, making Sardanpul of which the Greeks and Latins made Sardanapalus; and this Pul is supposed to be the same that reigned in Nineveh when Jonah preached the terrors of the Lord to that city.

That his hand - That is, his power and influence, might be with him: in this sense is the word hand frequently used in Scripture.