Albert Barnes Commentary Exodus 23:4-5

"If thou meet thine enemy`s ox or his ass going astray, thou shalt surely bring it back to him again. If thou see the ass of him that hateth thee lying under his burden, thou shalt forbear to leave him, thou shalt surely release [it] with him." — Exodus 23:4-5 (ASV)

So far was the spirit of the law from encouraging personal revenge that it would not allow a man to neglect an opportunity of saving his enemy from loss (Exodus 23:5).

The sense appears to be: “If you see the donkey of your enemy lying down under its burden, you shall refrain from passing by him; you shall help him in loosening the girths of the donkey.”