“Blessed are the pure in heart, for they shall see God.” (Matthew 5:8)
St John Cassian reminds us to set the right priorities in our spiritual life. Purity of heart is for him, the real goal of the Christian life and discipline. Purity of heart is equal in his teaching to love. Fasting is a tool to help us reach the goal, but as St. John notes, if we vent anger at others, fasting can’t compensate for the damage we do. It will not help our spiritual growth if we keep a strict fast but then rage at others or rail and rave against others. This last week of the Nativity Fast we would do well to work on peace in our hearts and purity – love for others. As St. Paul says in the Epistle read on the 2nd Sunday before Christmas: “But now you yourselves are to put off all these: anger, wrath, malice, blasphemy, filthy language out of your mouth” (Colossians 3:8). That should be what we really fast from this week.
“Everything we do, our every objective, must be undertaken for the sake of this purity of heart. This is why we take on loneliness, fasting, vigils, work, nakedness. For this we must practice the reading of the Scripture, together with all the other virtuous activities and we do so to trap and to hold our hearts free of the harm of every dangerous passion and in order to rise step by step to the high point of love.
It may be that some good and necessary task prevents us from achieving fully all that we set out to do. Let us not on this account give way to sadness or anger or indignation, since it was precisely to repel these that we would have done what in fact we were compelled to omit. What we gain from fasting does not compensate for what we lose through anger. Our profit from scriptural reading in no way equals the damage we cause ourselves by showing contempt for a brother. We must practice fasting, vigils, withdrawal, and the meditation of Scripture as activities which are subordinate to our main objective, purity of heart, that is to say, love, and we must never disturb this principal virtue for the sake of those others.” (John Cassian: Conferences, p. 41-42)
Truly God is good to the upright, to those who are pure in heart. (Psalms 73:1)