Charles Ellicott Commentary Job 41:25

"When he raiseth himself up, the mighty are afraid: By reason of consternation they are beside themselves." — Job 41:25 (ASV)

By reason of breakings — that is, the waves he makes in the water, or the breakings he makes among the plants and trees in the water.

They purify themselves — that is, they are beside themselves; they are so overwhelmed with terror, that they withdraw, as those who have to dwell apart for uncleanness.