It is necessary to remember this. People forget that the path of Christianity is indeed an ascetical labour. Last Sunday, we heard how the Lord said: "He that would come after Me, let him take up his cross, deny himself, and follow Me." The Lord said this with the greatest emphasis.
Therefore, the Christian must be one who takes up his cross, and his life, likewise, must be an ascetic labour of bearing that cross. Whatever the outward circumstance of his life, be he monk or layman, it is of no consequence. In either case, if he does not force himself to mount upwards,
then, of a certainty, he will fall lower and lower.
And in this regard, alas, people have confused thoughts. For example, a clergyman drops by a home during a fast. Cordially and thoughtfully, they offer him fasting food, and say: "For you, fasting food, of course!" To this, one of our hierarchs customarily replies: "Yes, I am Orthodox. But who gave you permission not to keep the fasts?" All the fasts of the Church, all the ordinances, are mandatory for every Orthodox person.
Speaking of monastics, such ascetics as Saint John of the Ladder and those like him fasted much more rigorously than the Church prescribes; but this was a matter of their spiritual ardour, an instance of their personal ascetic labour. This the Church does not require of everyone, because it is not in accord with everyone's strength. But the Church does require of every Orthodox the keeping of those fasts which She has established.
Oftentimes have I quoted the words of Saint Seraphim, and once again shall I mention them. Once there came to him a mother who was concerned about how she might arrange the best possible marriage for her young daughter. When she came to Saint Seraphim for advice, he said to her: "Before all else, ensure that he, whom your daughter chooses as her companion for life, keeps the fasts. If he does not, then he is not a Christian, whatever he may consider himself to be." You see how the greatest saint of the Russian Church, Saint Seraphim of Sarov, a man who, better than we, knew what Orthodoxy is, spoke concerning the fasts?
Sermon on The Ladder of Divine Ascent