What is "lending an ear"

Usage examples of "lending an ear".

Then, you recall, Miss Hoffman told us that the major was lending an ear when a certain lady called upon Benson the day he was shot.

How could it be that in the morning, on my knees at my bedside, or at night before lighted candles, I could pledge myself to goodness and the light, could appeal to God and renounce all sin forever and ever -- only to commit, perhaps but a few hours later, the most wretched betrayals of this same solemn oath and sincerest resolution, if only by chiming in with tempting laughter, or by lending an ear to a stupid schoolboy joke?