Isidore of Pelusium (Ancient Greek: Ἰσίδωρος ὁ Πηλουσιώτης, d. c.450) was born in Egypt to a prominent Alexandrian family.

[5] Following the example of John Chrysostom, whom he had managed to see and hear during a trip to Constantinople, Isidore devoted himself primarily to Christian preaching.

[3] Through the initiative of Isidore, the Third Ecumenical Council was convened at Ephesus (431), at which the false teaching of Nestorius concerning the person of Jesus Christ was condemned.

The historian Nicephorus states that Isidore wrote more than 10,000 letters to various people, in which he reprimanded one, advised another, consoled a third, instructed a fourth.

His letter to Tuba shows that it was considered unbecoming for a soldier to carry a sword in the city in time of peace and to appear in public with arms and military uniform.

A monk's habit should if possible be of skins, and his food consist of herbs, unless bodily weakness require something more.

Refrain from involving the living Church in your own private vengeance that is prosecuted out of a sense of duty to the dead.