Gratitude towards God is examined as a fundamental spiritual state, springing from an awareness of God’s gifts and culminating in the Holy Eucharist, understood as a complete union with Christ. Drawing on the teachings of Saints Cyril of Alexandria, Gregory Palamas, John Chrysostom, Dumitru Stăniloae and the Gospel passage on the healing of the ten lepers, the article demonstrates that authentic gratitude signifies a constant communion with God, whilst its absence leads to alienation and dehumanisation.