fall on knees
fall on (one's) knees
To kneel down, usually in a show of respect, fealty, awe, subjection, or reverence. The members of the congregation all fell on their knees to begin their morning prayer. I fell on my knees at the sight of the devastation.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
fall on one's knees
and fall to one's kneesto kneel down, usually in respect. The people fell on their knees and prayed in gratitude for their salvation from the flood. They fell to their knees in awe.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.