Maximus the Confessor (c. 580 – 662) was a 7th century Christian monk, theologian, and scholar who many contemporary scholars consider to be the greatest theologian of the Patristic era. Two of his most famous works are “Ambigua” – An exploration of difficult passages in the work of Pseudo-Dionysius and Gregory of Nazianzus, focusing on Christological issues, and “Questions to Thalassius” or “Ad Thalassium” – a lengthy exposition on various Scriptural texts. This quote is from the latter work. It affirms the primacy of experience in an authentic spiritual life.
“The scriptural Word knows of two kinds of knowledge of divine things. On the one hand, there is relative knowledge, rooted only in reason and ideas, and lacking in the kind of experiential perception of what one knows through active engagement; such relative knowledge is what we use to order our affairs in our present life. On the other hand, there is that truly authentic knowledge, gained only by actual experience, apart from reason and ideas, which provides a total perception of the known object through a participation by grace. By this latter knowledge, we attain, in the future state, the supernatural deification that remains unceasingly in effect.” ~ Ad Thalassium 60