It is, for the Orthodox, one of the most profound and mystical prayers and is often repeated endlessly as part of a personal [[asceticism|ascetic]] practice. There have been a number of [[Roman Catholic Church|Roman Catholic]] texts on the subject, but its usage has never achieved the same degree of devotion as in the Eastern Church. A more elaborate version known to some Roman Catholics by the same name goes: "O my Jesus, forgive us our sins, save us from the fires of Hell, and lead all souls to Heaven, especially those most in need of Your mercy."

In the Orthodox [[tradition]] the prayer is said or prayed repeatedly, often with the aid of a [[prayer rope]]. It may be accompanied by [[prostration]]s and the [[sign of the cross]]. As such, it is used as a means of finding contrition and as a means of bringing about humility in the individual; hence the words "the sinner" are sometimes added as if no other sinner existed but the person praying (though there is no indefinite article in Greek, thus leading to some controversy about whether the translation in English should be "the sinner" or "a sinner").