Fall on (one's) knees verb phrase
To go down on one or both of one's knees in order to express respect, awe, penitence, subjection or reverence
The monks fall on their knees and pray in the early morning.
People are falling on their knees and fold their hands to pray.
She fell on her knees and cried quietly.
He fell down on his knees in awe.
Believe that someone is a perfect person with no faults
To say or do something intentionally to show that you have disrespect for someone or something
To show too much respect to higher class people
To show absolute respect, admiration or love to someone
The verb "fall" should be conjugated according to its tense.
The origin of this expression is not clear.