knelt, knelled

Knelt or knelt is the past tense ( yesterday, or some time ago ) of "kneel", meaning to be on one's knees or to get on one's knees --
He knelt before the queen to receive the accolade.
He knelt down to look under the sink, and he bumped his head getting up.

Knelled or knelled is the past tense ( yesterday, or some time ago ) of "knell", meaning to ring once,  said of a bell, or the sound of a bell, most commonly meaning a deep, mournful tone --
The bell knelled once for each of the dead.
The old bell knelled its last; the chapel will be torn down next week.

Now that you know that, you can say--
"The congregation knelt to pray, as the bell knelled for their lost loved ones."