Charles Ellicott Commentary Exodus 22:4

"If the theft be found in his hand alive, whether it be ox, or ass, or sheep, he shall pay double." — Exodus 22:4 (ASV)

If the theft be certainly found in his hand. —If he had not appropriated it, consumed it, or, if it were an animal, killed it, then, instead of the fourfold or fivefold restitution of Exodus 22:1, a restoration of double was to suffice.