After spending a year on Skiropoul, the Monk Nicodemus returned to Athos, took monastic vows into the great schema and settled in the cell of Saint Theona in Kapsala. He agreed to take on a student, Hierotheus, and with even greater zeal devoted himself to working on books and instructing the brethren who settled around him in order to join in his wisdom.
Soon Saint Macarius of Corinth came to Athos again. He instructed St. Nicodemus to prepare a translation of the complete collection of works of St. Simeon the New Theologian. In the introduction to this book, which contained profound instructions on contemplation, St. Nicodemus clarifies that such writings are intended not only for monks, but also for laity, for all Christians are called to evangelical perfection. Then the Monk Nicodemus compiled the “Exomologitarium,” that is, the “Guide to Confession,” and a unique collection of canons to the Mother of God for each voice and for each day of the week for singing at the end of Vespers or at Compline in monasteries.
In addition to many other liturgical texts, he published two works at that time, which were adapted versions of two famous Western spiritual works: Lorenzo Scupoli's Invisible Warfare (1589) and Spiritual Exercises, which have continued to enjoy continued success. These books are by no means simple translations; they were deeply revised by the holy ascetic, who supplemented them with impeccable instructions on repentance, asceticism and the Jesus Prayer.
Meanwhile, “The Most Helpful Book of Continuous Communion” aroused sharp rejection among the monks, who defended the custom of receiving communion only three or four times a year, which contradicts the holy canons and apostolic Tradition. The book was accused of a newly invented heresy and condemned by Patriarch Procopius. But when Neophyte VII took the patriarchal throne (1789), the ban was lifted, and the Kollyvads were recognized as the true defenders of the sacred Tradition. Nevertheless, gross and absurd slander against St. Nicodemus continued to spread in some monastic circles. He was even accused of allegedly hiding the Holy Gifts in his skufa so that he could receive communion on the go. But the saint preferred to remain silent, awaiting justification only from God, and with tears he prayed for the conversion of those who were in error regarding the commemoration of the dead on Sundays.
Hieromonk Agapius of the Peloponnese came to Athos and invited St. Nicodemus to review and translate the collection of holy canons he had prepared, expanding the comments to it. The saint, for whom life and order in the Church were more valuable than his own life, set to work with zeal. He even took four scribes to quickly finish this necessary collection, which he called “The Helmsman” (“Pidalion”). For more than two years, the Monk Nicodemus worked day and night, collecting, comparing, correcting erroneous or contradictory texts, citing parallels from the decrees of the Ecumenical Councils, the Fathers of the Church and Byzantine civil legislation, enriching the work with a huge number of notes that provided precise criteria for the application of these canons in the life of the Church. The completed collection was sent to Constantinople, but he had to wait a long time for the patriarch's blessing. Then all the Athonite monks subscribed to this book, transferring funds. Then the collection was handed over to Hieromonk Theodoret, who was in Romania, for publication.
But he was an opponent of collivades and frequent communion and, at his own discretion, introduced corrections into the “Pidalion”, distorting the author’s intention and Church Tradition. The book was published in Leipzig in 1800. When it fell into the hands of the Monk Nicodemus, he was deeply offended and exclaimed: “It would be better if he struck me with a sword right in the heart than added or shortened anything in this book!”
At the same time, news reached St. Nicodemus that the manuscript of the complete collection of works of St. Gregory Palamas (November 14), collected and annotated with great difficulty by him at the request of St. Athanasius of Paria (June 24) and Metropolitan Leo of Iliopolis, was captured and destroyed in a Viennese printing house. This happened because the Austrians were looking for the "Manifesto" of Rigas Fereos, which called on the Greeks to revolt against the Turks. This news struck St. Nicodemus, and he shed streams of tears, regretting not so much the irreparable loss of time spent on this work, but the loss of such a treasure.
After this, the Monk Nicodemus, together with Sylvester of Caesarea, spent some time in the cell of St. Basil, where St. Theophilus the Myrrh-Streaming once lived (July 8), and then again began to live in solitude and continued his apostolic labors. Dressed in rags and wearing rough shoes, he considered himself the last of all. He never prepared any food for himself and ate only boiled rice or honey diluted with water, a few olives and a few soaked beans. If hunger tormented the Monk Nicodemus too much, he would come to his neighbors and eat with them, but usually he would immediately get carried away in conversation and forget about food. He was seen busy with only two things: prayer and scholarly works. At any hour of the day or night he could be found either bent over a book or writing implements, or with his head bowed on his chest, bringing his mind down into the depths of his heart, from there with zeal to call on the holy name of Jesus.
He became entirely prayerful, and it was thanks to this intimate unity with Christ that Divine grace placed in his heart the entire treasure of the Church. When the Monk Nicodemus wrote, he completely immersed himself in his work. One day a certain monk came to him and, finding him at work, put a piece of fresh bread into his mouth. In the evening he came in again and saw the Monk Nicodemus in the same position, with a piece of bread in his mouth, as if he had not noticed anything.
At this time, the Monk Nicodemus wrote an extensive commentary on the Epistles of the Apostle Paul, based on the interpretation of Blessed Theophylact of Bulgaria, adding also a commentary on the conciliar epistles. He also wrote an interpretation of nine biblical songs, entitled “The Garden of Grace,” and translated “Interpretation of the Psalter” by Evfimy Zigavin. As in all his other works, in these writings the Monk Nicodemus did not at all confine himself to simple translation. Taking as a basis and guide one of the commentaries accepted by the Church, he supplemented it with his extensive notes, saturating it with the testimonies of other Church fathers on many different issues.
Like an inexhaustible source, he published selected lives of ancient saints (“Neon Eclogion” - “New Izbornik”), and “New Martyrology” - a collection of the lives of the new martyrs to support the faith of Christians oppressed by the Ottoman yoke. Thanks to this collection, many apostates were converted and joined the glorious army of martyrs. The Monk Nicodemus constantly cared about the education of the people of God and published an essay entitled “Christian Good Morality” - a remarkable exposition of the moral instructions of St. John Chrysostom.
Every day, many of those who were wounded by sin or apostasy, bypassing bishops and confessors, flocked to the Kapsal ascetic to find spiritual healing and consolation. Not only monks, but also lay people came to St. Nicodemus from afar. The saint soon began to complain that he could not indulge in the prayer he desired, and again wanted to retire to a deserted place unknown to anyone. However, illness prevented him from realizing this intention.