The words above are in Kempis’s opening section in this chapter on how truth speaks within us (3,2). Here he echoes several Old Testament themes. Of particular note is the second part which finds its origins in Deut 32:2. We are also reminded of the miraculous manna in the desert that appeared nearly every day — after the dew evaporated — to the hungry and complaining Israelites in Exodus (see Ex 16; more on this below).
Jesus continues His Last Supper discourse today focusing on obeying the commandments (Jn 14:21-26). One cannot authentically claim to love Jesus and not obey Him. By keeping Christ’s words (that is, keeping the life of grace alive in us by not mortally sinning), we have the promise of the indwelling of the Trinity (Father and Son are mentioned above, the Holy Spirit [who “will teach you everything and remind you of all that I told you”] is mentioned at the end of the reading).
Kempis’s sentiments may well have been in the hearts of many of the men celebrating Passover with Jesus. This was a difficult time for everyone in the room and certainly they were seeking, in a special way, understanding of Jesus’ testament through docility of their troubled hearts. The Eleven, at least, truly loved the Lord, so would have been heartened to hear about the indwelling of God even if they did not understand how this would be accomplished; they would experience this very soon that evening, though. Jesus, as the new and perfect Manna, was about to give them His very self in the first Eucharist that He celebrated. But He had been giving Himself to them in word their entire time together over the past three years. His preaching was to settle like dew in their hearts turning into the true manna that comes from heaven.
We, too, should never miss an opportunity to show our love for Christ by inviting Him into our very being in Word and Sacrament at the Mass, and also through study and devotional reading of Scripture, alone or with friends, while asking the Lord to be with us often in spiritual communion.
Talk is cheap (see Mt 7:21). Our love for Christ is demonstrated through our actions. Let us always be docile and accepting of the truth of the Word so that we never lose the life of grace within us.
Detail from Institution of the Eucharist (1441) by Fra Angelico