Solomon prayed for the Lord to hear his people when they went into battle (2 Chronicles 6:34). In the battle against Zerah, God answered this prayer.
The term Cushite might refer to someone from southern Egypt (Nubia) or a Midianite area northeast of Aqabah (see Numbers 12:1; Habakkuk 3:7). However, several things suggest that Zerah was Egyptian:
The mention of Libya in 2 Chronicles 16:8
The battle's size (similar to Shishak's attack on Rehoboam in 2 Chronicles 12:3)
Mareshah's location in western Judah suggest Zerah
He is otherwise unknown. He might have been a Nubian general sent by Osorkon I, the Libyan pharaoh who ruled Egypt between the tenth and fourteenth years of Asa, around 900 to 897 BC. Another view is that Shishak created a buffer state around Gerar, supported by Nubian mercenaries who invaded Judah. The account, however, only states that Asa and his armies chased the enemy south to Gerar and took a large amount of plunder, especially from the herdsmen living in tents around the cities.