He was a member of the Modern Devotion, a spiritual movement during the late medieval period, and a follower of Geert Groote and Florens Radewyns, the founders of the Brethren of the Common Life.

While attending this school, Thomas encountered the Brethren of the Common Life, followers of Gerard Groote's Modern Devotion.

[5] After leaving school, Thomas went to the nearby city of Zwolle to visit his brother again, after Johann had become the prior of the Monastery of Mount St. Agnes there.

However, there is scant evidence to support that he was buried alive or the idea that the Church would have denied him sainthood if they did discover he died in this manner.

[citation needed] Kempis's 1441 autograph manuscript of The Imitation of Christ is available in the Bibliothèque Royale in Brussels (shelfmark: MS 5455-61).

[13] His important works include a series of sermons to the novices of St. Augustine Monastery, including Prayers and Meditations on the Life of Christ, Meditations on the Incarnation of Christ, Of True Compunction of Heart, Soliloquy of the Soul, Garden of Roses, Valley of Lilies, and a Life[14] of St. Lidwina of Schiedam.

If thou wilt receive profit, read with humility, simplicity, and faith, and seek not at any time the fame of being learned.

In angello cum libello [with slight variations] In a little corner with a little book A monument was dedicated to his memory in the presence of the archbishop of Utrecht in St Michael's Church, Zwolle, on 11 November 1897.