"Lord Jesus Christ have mercy on me"

This article is the meditation of a contemporary Athonite monk on the Jesus Prayer — "Lord Jesus Christ, have mercy on me" — translated from Greek and originally published in the journal *Synaxis* in 1984. The author develops a spiritual and ascetic reflection on the nature, practice, and effects of this hesychast prayer. The central idea is that the Jesus Prayer constitutes the preeminent means of uniting man to Christ and freeing him from the grip of the demon, acedia, and the passions. The theological contribution of this text lies in its living synthesis of the Athonite hesychast tradition: it articulates the anthropology of the heart, the doctrine of uncreated grace inherited from Gregory Palamas, and the cosmic dimension of prayer, while illustrating its argument with narratives and references to the Fathers, notably Symeon the New Theologian.