The point of the Christian life is not to become a better, more moral person. The end, the telos, is to become Christ: not just to be like Him, but to participate in His Life and His Body. If we think about this, though, this precludes all moral striving. No matter how hard we work, we will never be filled with the Holy Spirit and so share in the divine nature. Hence the necessity of faith, not just as rational (or even moral) assent, but coming under the authority and obedience of the King who offers the grace (Himself) so to do. To become Christ is the goal: who is Christ? He is the theandros, the God-Man, one who in His Person as the Word indivisably and unconfusedly unites the divine and the human natures. How are we in any way to attain to Him? We are human persons, who through faith in baptism are filled with the Holy Spirit who shares His nature with us. This is why the Spirit rested on Christ in His baptism; this is why our Lord did nothing without the Spirit in His sojourn; so that we might, as sons of God remade in the pattern of the Son of God, might be joined with the Spirit for our salvation. To acquire the Spirit, then, is the goal of the Christian life. To acquire the Spirit is to become Christ; to become Christ is to become divine, glorified, theotic. Here is where the central importance of the Tabernacle cultus and liturgy, detailed in the middle of the Torah, becomes so key: the Law was never about becoming moral, it was about becoming a Temple: pure, undefiled, holy. A place for God to dwell. The whole point of the commandments of God is not to make Him happy, as if our Lord needs that emotion (the One God dwells in blessedness of which happiness is but a pale shadow), no, the point of the commands is to be prepared for God's residence within us. But, just as the unclean always threatened the sanctity of the holy courts, so sin, death, Satan, and the disordered passions threaten Christ's Holy Temple, His Body, the Church. This makes the Law not about ascent to God to curry favor, but about guarding sacred ground: ethics, then, is priestly work.
This is why St Silouan the Athonite's dictum that "My brother is my life" is so important: the priests are not doing an individual task, but the collective work of protection and sanctification of the Church. I cannot do my work as a priestly guardian without reference to my brothers and sisters, nor without their constant aid and intercession so for strength and forgiveness of sins (which, to digress briefly, is why the communion of saints is so vital). All are saved together, none are saved alone.
It is worth noting that in the cultic regulation there are two categories of defilement: sin and symbols of death. Sin is, in Levitical terms, the conscious breaking of the Torah, which leads to death (whether as a consequence of the action, i.e. murder or the death penalty, or on the social level, i.e. adultery shredding families apart). The symbols, though, are those things that are not inherently sinful, but still reference death, especially as inherited through Adam. An example would be the regulations concerning childbearing (Lev. 12): after a woman gives birth, she must go through a period of ritual purification after the flow of blood dams. Then she must, if she is to readmitted to the Temple, offer a "sin offering." Why? Has she sinned? No, rather the term is better understood as "purification offering" (cf. Milgrom's commentary on Leviticus): since Eve, childbearing has been a sign of both hope ("your Seed shall crush the serpent's head...") and the consequences of death ("greatly will I increase your pains in childbearing"). A birth symbolizes the curse on Eve, but it is not insurmountable: there will come One who will save all women through being born by a virgin. This second category, the symbols of death, are fully dealt with by the destruction of death through the Resurrection. No longer do menstruations or child bearings make women unclean and disallowed from worship of the true God (one has only to reach in faith for the fringes of the Lord's garment to be fully healed!). Sin, however, remains as a defiling agent; here is why St Paul, for example, speaks of various actions, attitudes, and lifestyles as defiling or polluting the people of God.
To return to the main point, we know that the power of sin is strong enough, compelling enough (why else would our first parents even countenance the serpent?), and pervasive enough that we cannot resist it. Here is where our brothers and sisters come in, especially those who have had their passions healed and purified ("saints"): they can offer us forgiveness. Now, some might say, only God can forgive sins! True! God is the only One who forgives sins and He deigns to do it through the intercessions, through the rebukes, through the gentle and stern corrections of others. The root of forgiveness, which is often lost in our overly legal culture, is release: the Church, as the Body of the Christ, undoes the bonds that hold us tight. And the Lord promises (and warns) that if we forgive the trespasses of our brother and sister, our own trespasses are forgiven as well. We are set free as we set others free. This is the acquisition of the Holy Spirit, the forgiveness of the world. This is, not morals and ethics, but entering the Cross, actualizing baptism, becoming the body, sharing the One Loaf, salvation.