‘Bí a Íosa i m’ chroíse’ is one of the most popular native prayers in the Irish-language tradition but the text of the prayer has received only scant scholarly attention to date. The objective of this article is to initiate a discussion on the aesthetics and spirituality of the prayer-text by closely analysing its structure, poetic language and literary techniques. As the prayer is a Christian prayer in which Jesus is invited to dwell within the one who prays, the influence of Catholic theology on the subject matter and style of the prayer will also be examined. The close reading will, therefore, be preceded by a summary of the insights which may be gleaned on the internal presence of God from both Catholic theology and extant scholarship on native Irish prayers. Based on that summary, it will be argued in the textual analysis that elements of traditional native shield prayers for protection may be seen in ‘Bí a Íosa i m’ chroíse,’ and that it gives voice, especially, to Catholic teaching on the divine indwelling. Despite the emphasis placed in the prayer on the internal presence of God, however, it will also be demonstrated that the desired union with God does not happen within ‘Bí a Íosa i m’ chroíse,’ and that the last line of each verse, in particular, points to a struggle with a fear of alienation from God. Based on that analysis, this article tentatively speculates that the relevance for the modern believer of the text’s struggle with the presence and absence of God, could explain, in part at least, why ‘Bí a Íosa i m’ chroíse’ remains beloved as a prayer, and as a hymn, in the twenty-first century.