Ручьёв at Incendiary has thankfully begun the task of translating the letters of Fr Clement (Sederholm), the German-Russian who converted to Orthodoxy from Lutheranism and became a monk of Optina Pustyn'. The first translation was just posted, along with the promise of more.
[Following the request of Christopher at Orrologion, I have begun translating some selections from the letters of Fr Clement Sederholm (1830-1878) to his father. In the book I have acquired there are only 15 letters, and they are mostly from the period of Fr. Clement’s life after he was tonsured a monk at Optina in 1863 (ten years after converting to Orthodoxy). One feature that runs throughout all these letters is Fr Clement's unwillingness to openly argue with his father over points of theology. (Evidently at some point they did have such arguments as they are hinted at in early letters.) While in many letters Fr Clement talks about theological matters it is usually simply stating what the Orthodox believe or do, as in this first selection.]
I can briefly explain to you concerning prolonged prayers in our [Orthodox] Church. Every one of us prays not for himself only and not in their own way. We gather together for common church prayer in order to fulfill the unity and mutual love which is commanded by the Holy Spirit as well as what is prescribed by the apostle: forsake not the assembly as do some (Heb. 10:25). No matter how elevated the apostles stood they did not remove themselves from the assembly of believers (Acts 3:1). And that a few prayers of the Church are stronger than the prayers of one man can be seen from the fact that the Apostle Peter was freed from prison by the prayers of the Church (Acts 12:5-19). Our church prayers are made up of psalms, church songs, and various prayers. Every person praying follows the church prayers as they can: if his thoughts scatter he can quickly gather his senses and again follow after the course of the service and pray. But when someone prays alone and composes prayers himself then if his thoughts scatter it is harder for him for begin again to pray; and where does he start? If you, at your age and after long years of studying lofty subjects, feel how hard it is to keep your thoughts together, what can be said about a beginner? Concerning those who already reached the a high level of spiritual life, they add their short prayers to the common church prayer.
I heartily wish that my explanation turns out to be satisfactory to you.
October 26, 1863