An incident in the life of Saint Benedict, as taken from the following website: monksofadoration.org/tabmar95.html
Among his many miraculous works St. Benedict was known for a profound veneration of the holy Cross. Through the Sign of the Cross he worked many miracles and exercised power over demons. There is the famous story of someone poisoning St. Benedict’s wine. When he made the Sign of the Cross over the glass it broke harmlessly spilling out its deadly contents.
Another, more colorful version of the story can be found at this second website:
He [St. Benedict] told the brothers plainly that there were many comforts they must put away, and above all that they must eat less and work more.
Now the brothers did not like this at all, and they began to repent that they had asked so great a saint to come and rule over them, for he made their rule so hard and strict, that few of them cared to keep it.
Then one day a strange thing happened. The brothers were all dining together, and Benedict was silently eating his portion, his thoughts far away in the little mountain cell at Subiaco, when some one touched his arm and offered him a cup of wine. Benedict turned and looked searchingly into the brother’s face, and then with upraised hand made the sign of the cross over the cup. Instantly it fell broken to the ground, and the wine was spilt upon the floor, for there had been poison in the cup, which the holy sign had destroyed.
Then Benedict looked round at the company of brothers, who sat with downcast eyes, ashamed and silent, and, without a word, he rose and left them. He returned, alone as he had come, back to his mountain home, where instead of human voices there was the song of the birds, where the wild flowers looked at him with pure, friendly faces, and even the wild animals did not count him their enemy and would do him no harm.