Shishak ... came up ... because they had transgressed - The writer speaks from a divine, not a human, point of view. Shishak’s motive in coming up was to help Jeroboam, and to extend his own influence.
Related Commentaries of 2 Chronicles 12:2
2 Chronicles 12:2
2 And it came to pass, that in the fifth year of king Rehoboam Shishak king of Egypt came up against Jerusalem, because they had transgressed against the LORD,