New Revised Standard Version
Jeroboam had sent an ambush around to come on them from behind; thus his troops were in front of Judah, and the ambush was behind them.

Contemporary English Version
But while Abijah was talking, Jeroboam had sent some of his troops to attack Judah's army from behind, while the rest attacked from the front.

New American Bible
But Jeroboam had an ambush go around them to come at them from the rear; so that while his army faced Judah, his ambush lay behind them.

Douay-Rheims Bible
While he spoke these things, Jeroboam caused an ambushment to come about behind him. And while he stood facing the enemies, he encompassed Juda, who perceived it not, with his army.

While he spoke these things, Jeroboam caused an ambushment to come about behind him. And while he stood facing the enemies, he encompassed Juda, who perceived it not, with his army.

an ambushment

2 Chronicles 20:22 And when they began to sing praises, the Lord turned their ambushments upon themselves, that is to say, of the children of Ammon, and of Moab, and of mount Seir, who were come out to fight against Juda, and they were slain.

Joshua 8:4 And commanded them, saying: Lay an ambush behind the city: and go not very far from it: and be ye all ready.

Proverbs 21:30 There is no wisdom, there is no prudence, there is no counsel against the Lord.

Jeremiah 4:22 For my foolish people have not known me: they are foolish and senseless children: they are wise to do evil, but to do good they have no knowledge.