What is the “misery of man” that Kempis speaks of in this chapter (1,22)? It is not only our worldly desires but even our physical needs. To the extent that these pull us away from God, they are problematic. Thus the pressing need to eliminate sin and mortify the body; that is, to loosen our attachments in this brief life so as to better prepare for life eternal.
Jesus also frequently spoke of the Kingdom (in fact, today’s evangelist’s Gospel [Mt 5:17-19] is sometimes called the Gospel of the Kingdom). He ushered in the Kingdom here on earth (see Mk 1:15 and Jn 11:23-25) but wants us to remain focused on the next life. How we behave here and now determines our eternal destination (Jesus speaks plenty about hell as well throughout the Gospels; in fact, just read the remainder of this chapter to get a heavy dose).
Considering the words of Kempis, we see how detachment from sin and material needs keeps us focused on the next life. When this disposition becomes habitual (with God’s grace and our cooperation), the danger of being led astray or leading others astray diminishes, thus honoring Jesus admonition to obey God’s commandments ourselves and teach these commandments to others. This is not optional. The failure to do so has never-ending consequences.
Sermon on the Mount, Scenes from the Life of Christ (6th c.) from the Byzantine School