Christ expressly derived this commandment from the law of love. He gave numerous commandments, among which five in the Sermon on the Mount are notable; "these commandments do not constitute the teaching, they only form one of the numberless stages of approach to perfection";[920] they "are all negative, and only show"[921] what "at mankind's present age"[922] we "have already the full possibility of not doing, along the road by which we are striving to reach perfection."[923] The first of the five commandments of the Sermon on the Mount reads "Keep the peace with all, and if the peace is broken use every effort to restore it";[924] the second says "Let the man take only one woman and the woman only one man, and let neither forsake the other under any pretext";[925] the third, "make no vows";[926] the fourth, "endure injury, return not evil for evil";[927] the fifth, "break not the peace to benefit thy people."[928] Among these commandments the fourth is the most important; it is enunciated in the fifth chapter of Matthew, verses 38-9: "Ye have heard that it was said, Eye for eye, and tooth for tooth. But I say to you, Resist not evil."[929] Tolstoi tells how to him this passage "became the key of the whole."[930] "I needed only to take these words simply and downrightly, as they were spoken, and at once everything in Christ's whole teaching that had seemed confused to me, not only in the Sermon on the Mount but in the Gospels altogether, was comprehensible to me, and everything that had been contradictory agreed, and the main gist appeared no longer useless but a necessity; everything formed a whole, and the one confirmed the other past a doubt, like the pieces of a shattered column that one has rightly put together."[931] The principle of non-resistance binds together "the entire teaching into a whole; but only when it is no mere dictum but a peremptory rule, a law."[932] "It is really the key that opens everything, but only when it goes into the inmost of the lock."[933]