This medieval Irish sermon was a theological discourse on the distinction between St. John and St. Peter, highlighting John's superior contemplative grasp of divine truths. It asserts that John, through his profound understanding of the Word, transcends both visible and invisible creation, while Peter represents action and faith. The author underscores John's unique role in revealing deep theological mysteries, particularly regarding the nature of Christ and the unity of the Trinity. The text concludes by portraying John as a figure who surpasses human limitations and comprehends the essence of God.