What does Judges 5:10 mean?

In verse 3, Deborah had directly addressed the kings and princes of Canaan, telling them to listen as she sang her victory song to the Lord. This can be read as taunting after the Lord's victory over Canaan—which, in a sense, it is (1 Kings 18:26–27). It is certainly meant to emphasize that the God of Israel defeated them.

Now she turns her eyes to the wealthy, perhaps thinking specifically of those who continued to go about their successful business, making money and enjoying life while Israel was being so cruelly oppressed. White or pale donkeys might have been more prized and more expensive. More likely, this refers to the ornate saddles and covers used by rich people. The wealthy could drape expensive rugs over their white donkeys and ride in both comfort and style. These merchants likely profited from Israel's enslavement to the Canaanites. Another possible meaning for this reference is joy over the end of Canaan's oppression, which would allow merchants to trade their goods once again (Judges 5:6).

Deborah also mentions those who walk by the way, not riding on donkeys. In this context, the reference is meant as a contrast: a reference to the poor. She means for people of all classes to distribute her song everywhere. She wants the fame of God's victory over Canaan to spread.