Chapter 26 of the Book of the Prophet Isaiah, to which the verses you are inquiring about belong, contains a unified poetic work, the "Hymn of Isaiah." It was composed by an unnamed follower of the prophet Isaiah, who lived in the mid-6th century BC and is traditionally referred to as Deutero-Isaiah. This hymn (which is widely used, incidentally, in Orthodox liturgical worship) is part of a larger text (chapters 24-27), the so-called Apocalypse of Isaiah. Through poetic means, employing historical analogies characteristic of his tumultuous era, Deutero-Isaiah depicts God's impending victory over sin and death. As in other texts by Deutero-Isaiah (who authored the entire second half of the Book of Isaiah, beginning with chapter 40), historical cataclysms here (in particular, the wars between the Persian and Babylonian empires) serve as prefigurations of God's intervention in history. This also applies to the verses in question.

The differences between the texts of the Septuagint and the Vulgate, as well as between the Slavonic and Russian Bibles, can be attributed to the fact that in ancient Israel there were several versions of the text, preserved and transmitted by different groups of scribes. The ancient Hebrew text, preserved in the Masoretic version, was transmitted by the scribes of Jerusalem; the Vulgate follows it, and the Russian Synodal translation was made from it. The Alexandrian Jews preserved and transmitted their own version of the text (perhaps even more than one); the Greek translation (the Septuagint) was made from this version. The Slavonic text was primarily translated from the Greek (especially those passages incorporated into liturgical worship) and was partially (though not entirely) revised according to the Vulgate in the 15th century.

In the Sermon on the Mount, the Lord Jesus Christ Himself explains these words quite clearly, saying, "do not resist an evil person". In human society, including in Israel during the time of Christ's earthly life, the widespread opinion is that violence must be avenged. The main commandments of the Old Testament seek only to confine this vengeance within certain limits, requiring that retribution for violence be commensurate with the violence itself.

However, the Lord says, it is impossible to overcome evil and violence in this way. What then is to be done? Through His entire life, the Lord shows us the way to stand against evil; it is the way of love and forgiveness, faithfulness to God, and the acceptance of suffering. This path led Jesus Himself to the Cross, and only the Resurrection of Christ testifies to all His disciples that this is the only way to stand against evil.

As for the specific phrase that prompted your question — one must admit it is shocking. But, you must agree, such an extreme degree of rejecting violence as a response to violence has proven to be more than memorable. Even in atheistic societies, through culture, it is absorbed into people's minds, compelling us to think about it.

In practice, striving to follow these words leads to the realization that we are not alone in the suffering inflicted upon us by people: the Lord takes this suffering upon Himself. And if we dedicate our rejection of violence to Him, He grants us an incomparable joy that no violence can take away from us. The only thing to bear in mind is that each of us is called to respond in this way to the violence inflicted upon us personally. Violence inflicted upon others requires a different response.

Both of these biblical texts, so different at first glance, reflect a single understanding of life.

The foundation of the understanding of life in Ecclesiastes is, perhaps, that within the framework of earthly life everything that seems valuable and significant to man is, in fact, vanity and a chasing after the wind. Ecclesiastes seeks and finds nothing on earth to which the heart should be attached, which could become a source of happiness, a source of life for man. Even wisdom and moderation, so valued by the ancients, give us nothing but privation, even voluntary privation. Only in God does Ecclesiastes hope to find meaning; but God remains incomprehensible and distant to him. To draw near to Him is hardly possible for man.

The understanding of life in Ecclesiastes is colored by inescapable sorrow, because in this life he sees suffering and emptiness behind everything. The book ends with an unspoken hope for "that day" when the sun and stars will grow dim, and this earthly world will come to its end. The "Day of the Lord," the "Day of Judgment," as the great prophets of the Old Testament called it, may perhaps give man some understanding of the meaning of existence. But the light of this hope is hidden from Ecclesiastes; written in the period between the return from the Babylonian captivity and the coming of Christ, this book sums up the hopeless, joyless, and meaningless existence of man before Christ. The sorrow of Ecclesiastes is such that nothing earthly can quench it, and in this lies the greatest realism of this book.

The fundamental meaning of the understanding of life behind the words of the Lord Jesus Christ in the Sermon on the Mount is that only God Himself can be the answer to all our questions. The only thing that can be the purpose and meaning of human life is God Himself. Not something proceeding from Him, not earthly life in itself, nor even eternity can quench the thirst resounding in the words of Ecclesiastes. Only God… And the most important thing that the Lord Jesus proclaimed to people is that God has come to us to give us meaning, joy, and life. Even suffering becomes for us not just a symptom of mortality, but a meeting place with the Incomprehensible. Deeds of mercy and the fulfillment of the law, meekness and the rejection of violence, love for people itself — everything gains meaning only because here we find God. "The kingdom of heaven is at hand," the Lord repeats more than once in the Gospel. That Kingdom where life finds meaning, that for which it would be worth living, is inaccessible to us — but this Kingdom itself has drawn near to us out of God's great love.

In Christ, man finds what Ecclesiastes sought and did not find. But nowhere else but in Him can this be found — in this both the book of Ecclesiastes and the Sermon on the Mount converge. Of course, this answer is necessarily brief and most likely incomplete. If we briefly answer your second question in the same way, it will be something like this: The purpose of our life is God Himself, a Person whom one can love, seek, comprehend, and trust. At the same time, the purpose of our life is to fulfill God's design for us: to bring His love into the created world, to serve as a creative principle in the world. This is possible for us only together with God; by ourselves we can create nothing but chaos. These two aspects of the purpose of our life unite in the possibility of being the presence of God in this world, a Temple of the Holy Spirit, as the apostle Paul expresses it.

The meaning of life is thus hidden in the Almighty Himself. As Saint Augustine, the great Christian thinker of the late 4th — early 5th centuries, said addressing God: "You have made us for Yourself, and our hearts are restless until they find their rest in You." The Lord Jesus Christ Himself expressed this mystery in the words of a prayer addressed to the Father: "That they may all be one, just as you, Father, are in me, and I in you, that they also may be in us." The love that unites us with God to the very depths of our and His nature — this, perhaps, is the meaning of our life. The value of human life I would measure by God's love for each of us. We are weak, empty, and barren; our life often seems worthless to us. But God loves us not because we are good, but because He is God. And we are valuable not because we are good, but because we are loved by Him.

It is unlikely that this answer can claim completeness and objectivity. But, I hope it is direct enough. Practice shows that it hides a wonderful power of life; moreover, it is important to bear in mind that when we meet God, questions disappear. Not that we receive answers, — but there comes a moment when you forget about questions and begin to live, because God Himself is the answer to everything.