He doesn't trust himself.

The poor sinner, who has committed so many great sins that she does not deserve to dwell in God's house, does not trust in herself, but believes only in the worshiped Trinity, in Jesus the Crucified, in the Most Holy Sacrament, and in the most holy Virgin, calls upon her dearest sisters Elizabeth of the Trinity and Teresa Eugenia of the Eucharist to three virtues:
1. to inner recollection, rejecting every useless thought that does not lead us to God;
2. to inner and outer silence and to the effort not to speak unless necessary;
3. to obedience even in the slightest indication and to the subjection of our reason.

(Teresa of Los Andes, the formula with which she turned to her fellow sisters in the novitiate on the 1st Sunday of Advent 1919 according to Carmelite tradition)