Commentary on the Bible, by Adam Clarke, [1831], at sacred-texts.com
Rehoboam and his subjects, forsaking the Lord, are delivered into the hands of Shishak, king of Egypt, Ch2 12:1-4. Shemaiah the prophet remonstrates with them, and they humble themselves, and Jerusalem is not destroyed; but Shishak takes away all the treasures, and the golden shields, instead of which Rehoboam makes shields of brass, Ch2 12:5-12. He reigns badly seventeen years, dies, and is succeeded by his son Abijah, Ch2 12:13-16.
He forsook the law of the Lord - This was after the three years mentioned Ch2 11:17.
Shishak king of Egypt - Concerning this man, and the motive which led him to attack the Jews, see the note on Kg1 14:31.
Transgressed against the Lord - "Against the Word of the Lord." - Targum.
The Lubims - Supposed to be a people of Libya, adjoining to Egypt; sometimes called Phut in Scripture, as the people are called Lehabim and Ludim.
The Sukkiims - The Troglodytes, a people of Egypt on the coast of the Red Sea. They were called Troglodytes, Τρωγλοδυται, οἱ τας τρωγλας οικουντες, "because they dwelt in caves." - Hesych. This agrees with what Pliny says of them, Troglodytae specus excavant, haec illis domus; "The Troglodytes dig themselves caves; and these serve them for houses." This is not very different from the import of the original name סכיים Sukkiyim, from סכה sachah, to cover or overspread; (hence סוך such, a tabernacle); the people who were covered (emphatically) under the earth. The Septuagint translate by the word Τρωγλοδυται, Troglodytes.
The Ethiopians - כושים Cushim. Various people were called by this name, particularly a people bordering on the northern coast of the Red Sea; but these are supposed to have come from a country of that name on the south of Egypt.
Whereupon the princes of Israel and the king humbled themselves - This is not mentioned in the parallel place, Kg1 14:25-29 : this was the sole reason why Jerusalem was not at this time totally destroyed, and the house of David entirely cut off; for they were totally incapable of defending themselves against this innumerable host.
They shall be his servants - They shall be preserved, and serve their enemies, that they may see the difference between the service of God and that of man. While they were pious, they found the service of the Lord to be perfect freedom; when they forsook the Lord, they found the fruit to be perfect bondage. A sinful life is both expensive and painful.
Took away the treasures - Such a booty as never had before, nor has since, come into the hand of man.
The shields of gold - These shields were the mark of the king's body-guard: it was in imitation of this Eastern magnificence that Alexander constituted his Argyraspides, adorned with the spoils taken from Darius. See Quintus Curtius, lib. viii., c. 5, et alibi.
Was one and forty years old - Houbigant thinks he was but sixteen years old when he began to reign; and brings many and forcible arguments to prove that the number forty-one must be a mistake. That he was young when he came to the throne, is evident from his consulting the young men that were brought up with him, Ch2 10:8, Ch2 10:10. They were young men then; and if he was brought up with them, he must have been young then also. Besides, Abijah, in his speech to Jeroboam, Ch2 13:7, says that at the time Rehoboam came to the throne he was tender-hearted, and therefore could not withstand the children of Belial raised up against him by Jeroboam: but surely at that time no man could be reputed young and tender-hearted - quite devoid of experience, who was above forty years of age. Besides, if this reading were allowed, it would prove that he was born before his father Solomon began to reign, for Solomon reigned only forty years, and Rehoboam immediately succeeded him.
Concerning genealogies - "In the book of the genealogy of the family of David." - Targum.
Abijah his son - Concerning the many varieties in this king's name, see the note on Kg1 14:31.