[4] The Ascetical Homilies seem to be written primarily for an audience of Eastern Christian monastics, although the book has proved beneficial to both laity and tonsured.

With sharp vividness he speaks about themes relevant to every Christian: about repentance and humility, about prayer in its many forms, both outer and inner, about solitude and community, about silence, wonder, and ecstasy.

"[5] In the book, Isaac teaches the process of noetic purification through ascetic labors, especially that of hesychasm and nepsis, using frequent references to both scripture and the Holy Fathers.

And again, in Homily 72, "But lo, the majority of men to not attain such innocency... For in all the measures of every way upon which each man journeys to Him, God opens before him the gate of the Kingdom of the Heavens."

Like his contemporary, Maximus the Confessor, Isaac understands the divine love to function as both the joy of the holy and the torment of the evil.

"[20] Explaining the purpose of his writings, Isaac says, "I now compose this homily for the kindling and enlightenment of our souls, and of those who come across it, with the hope that, perchance, some might rouse themselves by reason of their desire for what I speak of, and endeavor to practice it."

[22] The Ascetical Homilies are directly quoted in the Evergetinos, in the Life of Saint Cyril of Philea, and in the Philokalia by Peter of Damascus.

According to him, Daniel Bar Tubanitha, the Bishop of Beth Garmai c. the 7th century, found fault with three propositions in Isaac's writings.

[2][28] More recently, The Ascetical Homilies have been rejected by some due to incorrect accusations that Isaac was a Nestorian—an idea which Paisios the Athonite strongly opposed.

[29] As Eric Jobe wrote, "...even if we acknowledge, as scholars unanimously do, that St. Isaac was the Eastern bishop of Nineveh, this does not necessitate that he had a thoroughly Nestorian Christology."

"[5] Some scholars, such as Alexei Sidorov, argue that there was a pro-Chalcedonian (and anti-Nestorian) movement within the Churches of the East at that time, and that Isaac could very well have been a proponent of this Chalcedonian Christology.

[30] Within a hundred years of Isaac's death, his The Ascetical Homilies were already famous, and were referred to and quoted from in Syriac literature.