There is a sin which is always 'unto death' [1 Jn 5:16]; the sin which we have not repented. Even a saint's prayers will not be heard for the unrepented sin. The person who repents correctly does not imagine that his sins are cancelled through his own effort; but knows that through this effort he makes peace with God.
When you are praying alone, and your spirit is dejected, and you are wearied and oppressed by your loneliness, remember then, as always, that God the Trinity looks upon you with eyes brighter than the sun; also all the angels, your own Guardian Angel, and all the Saints of God. Truly they do; for they are all one in God, and where God is, there are they also. Where the sun is, thither also are directed all its rays. Try to understand what this means.
The lives of men are subject to drastic changes. These changes are gradual at times; at others, lightning quick. But even those of us who enjoy long years of opulence and fame can find no consolation, no gladness, unless our heart is illumined by the steady light of peace. It is this peace that we must seek, it is for this peace that we should pray. The peace that our Lord gave to His disciples and to all those who really have faith in him.
Do not attempt to assess the quality of your prayer. God alone can judge its value. To us, our own prayer must always appear so poor an effort, so inadequate an achievement, that the cry of the publican spontaneously rises from our lips.
If a man has some spiritual gift and feels compassion for those who do not have it, he preserves the gift because of his compassion. But a boastful man will lose it through succumbing to the temptations of boastfulness.
The joint prayer of husband and wife is a great force. That may be one of the reasons why the enemy is trying to get both of you to break this excellent habit. [This is] one more temptation which God permits so that you should learn to overcome it and come out of the testing stronger than before!
Bear this in mind: the Christian life is an unending spiritual fight. The wily enemy cleverly uses snares and arrows without number. Before some of us he spreads the lure of worldliness, the outer pride of pomp and circumstance, the cruder lusts-the lusts of the flesh. But those of us who are not attracted by any of this he leads up on to the peaks of subtler prides. Having got us there-to the high country of self-esteem-he causes a dark mist, the mist of the subtlest prides, to enshroud our intellect. Then he leads us, his blinded slaves, away from God, without our even suspecting it. Mark this too: it is not very hard for the simple sinner to come to hate his foul life and, leaving it, to fling himself on the mercy of God; but it is very hard for the subtler sinner-the self-sufficient one-to let a ray of divine love pierce the leather jacket of his self-righteousness... Humility is the only weapon that wards off all attacks, but it is difficult to fashion, and the art of using it is often misunderstood, particularly by those who lead an active, worldly life.
You are, I am sure, aware that for you penitence is now no longer limited to disclosing your sins to your confessor, but that you must now bear your sins in mind always, until your heart nearly breaks with their ugly load; and would break, were it not for your firm faith in the mercy of our Lord.