A house roof is held up by the foundations and the rest of the building, and the foundations with the rest of the building are laid to hold the roof - since both are necessary and useful - and neither is the roof built without the foundations and the rest of the house, nor can foundations and walls without a roof make a building fit to live in. So it is with the soul: the grace of the Holy Spirit is preserved by keeping the commandments, and the keeping of commandments is the foundation laid for receiving the gift of God's grace. Neither does the grace of the Holy Spirit remain in us without our obeying the commandments, nor can obeying the commandments be useful and salutary without Divine grace.
If the soul is vigilant and withdraws from all distraction and abandons its own will, then the spirit of God invades it and it can conceive because it is free to do so.
Peter was first given the keys, but then he was allowed to fall into the sin of denying Christ; and so his pride was humbled by his fall. Do not be surprised, then, if after receiving the keys of spiritual knowledge you fall into various evil thoughts. Glorify our Lord, for He alone is wise: through setbacks of this kind He restrains the presumption that we tend to feel because of our advance in the knowledge of God. Trials and temptations are the reins whereby God in His providence restrains our human arrogance.
We should look upon every believer alike, and suppose that Christ abides in each; we must have such loving disposition towards him as to be ready to lay down our life for him. We should never think or say that someone is evil, but, as is said, should see everyone as good. If you see someone attacked by the passions, hate not the brother but the passions attacking him.
A great effort and much toil are needed in prayer before we can reach a state in which our mind is no longer troubled, and so attain the inward heaven of the heart where Christ dwells. As St. Paul says, 'Do you not realize that Christ dwells within you, unless you are worthless?' (cf. 2 Cor. 13:5).
A single word made the thief pure and holy, despite all his previous crimes, and brought him into paradise (cf. Luke 23:42-43). A single ill-advised word prevented Moses from entering the promised land (cf. Num. 20:12). We should not suppose, then, that garrulity is only a minor disease. Lovers of slander and gossip shut themselves out of the kingdom of heaven.
The kingdom of God is always present for him who desires and wills it. When a man's disposition and way of life are like that of an angel, most assuredly this is the kingdom of God. For God indeed is said to rule as King when nothing worldly meddles in the governing of our souls and when in every respect we live not of this world. This manner of life we have within us, that is to say, we have it within us when we desire and will it. We do not need to wait a long time, or until our departure from this life; instead, faith and a God-pleasing life which accompanies faith are very near us.
It seems to me that few people understand the extent of the cunning wickedness of these demons and the way in which they assist one another. I have known the demon of cowardice to fight and work together with that of listlessness. One comes to the aid of the other and reinforces him. The first brings fear and obduracy into the soul, the second produces darkness, negligence, blindness of heart and mind, and finally despair. Listlessness is a real trial for all those engaged in the spiritual struggle, but it becomes for them the ambassador of humility.
As a blacksmith can do nothing without the help of fire, however skilled he may be in wielding his tools, so a man should do everything he can on his side to purify his heart, using virtues as tools for this purpose; but without fire of the Spirit, everything he does will remain inactive and useless for his aim, for by itself what he does is powerless to cleanse the soul of its dirt and foulness.
Mourning has a twofold action: like water tears extinguish all the fire of passions and wash the soul clean of their foulness; and, again, through the presence of the Holy Spirit, it is like fire bringing life, warming the heart, and inciting it to love and desire God.