They say that Abba Macarius the Egyptian [St. Macarius the Great] on one occasion went up from Scete to the Nitrian mountain, and as he drew near to a certain place, he said to his disciple, "Pass on a little in front of me"; and when he had done so there met him a certain heathen priest, who was running along and carrying some wood about the time of noon. And that brother cried out to him and said, "O minister to devils, where run thou?"  And the priest turned round and smote him with many severe blows, and he left him with but very little breath remaining in him, and he took up his wood and went on his way; and when he had gone on a little further the blessed Macarius met him on his journey, and said to him, "May you be helped, O man of labours?"  And the priest was astonished, and came to him and said, "What fair thing have you seen in me that you should salute me [in this gracious fashion] ?"  And the old man said to him, "I see that you toil, and that you do not know that you are toiling for naught"; then he said to the old man, "At your salutation I also was very sorry, and I learned that you did belong to the Great God. But a wicked monk met me just before you didst, and he cursed me, and I smote him even to death."  And the old man knew that it was his disciple [of whom he spake], and the priest laid hold upon the feet of Macarius, and said to him, "I will not let you [go] until you make me a monk"; and they came to the place where the brother was lying, and they carried him and brought him to the church of the mountain. Now when the fathers saw the heathen priest with him, they marvelled that he had been converted from the error which he had held; and Macarius took him and made him a monk, and through him many of the heathen became Christians. And Abba Macarius said, " ' An evil word makes wicked even those who are good, and a good word makes good even those who are wicked,' as it is written."

from Sayings of the Holy Desert Fathers