Here is a sermon by St. Theodosius' Sermon to his monks entitled "On Patience and Love." Taken from A Treasury of Russian Spirituality by G. P. Fedotov (1886-1951)
Beloved, what did we bring into this world, or what have we to take out of it? Did we not leave the world and worldly things according to the commandment of Christ, Who said, "Every one of you that doth not renounce all that he possesseth, cannot be my disciple"; and again, "If anyone love me, he will keep my word"? Love of God is expressed not in words but in actions. For He said: "He that hath my commandments and keepeth them, I will love him, and will manifest myself to him. A new commandment I give unto you, that you love one another, as I have loved you." And "In this," He said, "is my Father glorified; that you bring forth very much fruit, and become my disciples."
Is it not of itself astonishing, beloved, that God can be glorified by works of ours - and what love He pours out upon us, wretches that we are: "As the Father hath loved me, I also have loved you... Greater love than this no man hath, that a man lay down his life for his friends"; and, "You are my friends." What then should we, miserable men, be like? Does not our heart burn, hearing these words? ... What good did we do to Him, that he has chosen us and rescued us from this transient life? For have not we all gone astray and became useless in His work, following our lusts? Yet He did not despise us in such an evil condition; he did not abhor our nature, but having taken the form of a slave, became like us. And all this He did that we may be saved.