Which lines from "The Inchcape Rock" best support the inference that the bell the Abbot put on the rock saves lives?

"The buoy of the Inchcape Bell was seen, A darker spot on the ocean green;"

"So little they rose, so little they fell, They did not move the Inchcape Bell."

"On a buoy in the storm it floated and swung, And over the waves its warning rung."

"When the rock was hid by the surges’ swell, The mariners heard the warning bell;"