He was a disciple of St Arsenios the great and abbot of the Scetis in Egypt (the monastic system known as the "Skete" takes its name from Scetis). He lived the communal monastic life for forty years, then in 420 retired to the desert, where he remained until his repose.
From the Prologue: "A saint has a very sensitive conscience. What ordinary people may consider a small sin, a saint sees as a great crime. It is said of Abba Daniel that highwaymen attacked him on three occasions and took him off to the mountains. Twice he was rescued, but the third time, in attempting to escape, he struck one of them with a stone and killed him, and then made his escape. That murder lay on his conscience like a lead weight. In perplexity as to what he should do, he went to Timothy, the Patriarch of Alexandria, and asked his advice. The Patriarch soothed him, and released him from all penance. But his conscience continued to gnaw at him, and he went to Rome, to the Pope. The Pope gave him the same reply as had the Patriarch. Still dissatisfied, Daniel visited the remaining patriarchs in turn; going to Constantinople, Antioch and Jerusalem, confessing to each of them and asking for advice. But he could find no peace. So he returned home to Alexandria and declared himself to the authorities as a murderer, and was flung into prison. At his trial before the governor, Daniel told how everything had come about, and pleaded that he might be killed too, that his soul might be saved from eternal fire. The governor was amazed at the whole thing, and said to him: 'Go your way, Father, and pray to God for me, even if you kill seven more!' Still dissatisfied with this, Daniel resolved to take a leper into his cell and care for him until he died, and then find another. He did as he had resolved, and in this way brought peace to his conscience."