About a mile from the holy River of Jordan...

…there is a place which is known as the Lavra of the holy Abba Gerasimos. When we were there, the residents told us that this St. Gerasimos was walking one day by the banks of the holy Jordan when he met a lion, roaring mightily with pain in its paw. The point of a reed was deeply embedded in it, causing inflammation and suppuration. When the lion saw the elder, it came to him and showed him the foot, wounded by the point embedded in it whimpering and begging some healing of him. When the elder saw the lion in such distress, he sat down and, taking the paw, he lanced it. The point was removed, and also much puss. He cleansed the wound well, bound it up and dismissed the beast. But the healed lion would not leave the elder. It followed him like a noble disciple wherever he went. The elder was amazed at the gentle disposition of the beast and, from then on, he began feeding it, throwing it bread and boiled vegetables.

Now the lavra had an ass which was used to fetch water for the needs of the elders, for they drink the water of the holy Jordan; the river is about a mile from the lavra. The fathers used to hand the ass over to the lion, to pasture it on the banks of the Jordan. One day when the ass was being pastured by the lion, it went away some distance from its keeper. Some camel-drivers on their way from Arabia found the ass and took it away to their country. Having lost the ass, the lion came back to the lavra and approached Abba Gerasimos, very downcast and dismayed. The abba thought that the lion had devoured the ass. He said to it, “Where is the ass?” The beast stood silent, hanging its head, very much like a man. The elder said to it, “Have you eaten it? Blessed be God! From henceforth you are going to perform whatever duties the ass performed.” From that time on, at the elder’s command, the lion used to carry the saddle-pack containing four earthenware vessels and bring water.

One day an officer came to ask the elder for his prayers, and he saw the lion bringing water. When he heard the explanation, he had pity on the beast. He took out three pieces of gold and gave them to the elders, so that they could purchase an ass to ensure their water supply, and that the lion might be relieved of this menial service. Sometime after the release of the lion, the camel driver who had taken the ass came back to the Holy City to sell grain and he had the ass with him. Having crossed the holy Jordan, he chanced to find himself face to face with the lion. When he saw the lion, he left his camels and took to his heels. Recognizing the ass, the lion ran to it, seized its leading rein in its mouth – as it had been accustomed to do – and led away, not only the ass, but also the three camels. It brought them to the elder, rejoicing and roaring at having found the ass which it had lost. The elder had thought that the lion had eaten the ass, but now he realized that the lion had been falsely accused. He named the beast Jordanes, and it lived with the elder in the lavra, never leaving his side, for five years.

John Moschos, Leimonarion (The Spiritual Meadow) 107
Abba Gerasimos of the Jordan, commemorated 4 March
icon and troparion at: http://www.comeandseeicons.com/g/ati04.htm