I heard this in the 1970's, supposedly about Brother Lawrence. That is plausible, yet I suspect this did not actually happen. Consider it a parable.
An elderly monk had a reputation for wisdom, and locals requested of the abbot that they be allowed to ask his advice, which was often granted. The monk would invite them to join in whatever work he was doing at the time as they poured out their stories. His fame spread slowly and quietly, but widely.
In time a cardinal came by, traveling to see all his charges, and asked - or demanded - of the abbot to speak with the monk with the wide reputation. The abbot agreed, but rather than accompany the cardinal he merely told him the man he sought was working in the kitchen and pointed the way.
The cardinal thus came in behind the monk, who was scrubbing the floor with a brush, and said "I have heard you are a person of great wisdom and piety. Could you tell me what wisdom you have?"
"Certainly," said the monk, not looking up but holding a brush out behind him and upwards. "Come join me."
"I don't think that would be proper," said the cardinal with a hint of a smile.
"If you can't come down I can't explain it to you."