The sectarians emphasized (1) that humans were worthless bits of nothing and depended absolutely on God’s grace, and (2) that they were capable of becoming and remaining perfect. These statements are more radical than Josephus’, but they are not fundamentally different.
The world is still full of people who will focus on one of these themes, usually human effort in attaining perfection, and conclude that the sectarians in particular and Jews in general believed in the sort of meritorious achievement that is called legalistic self-righteousness. And they will maintain that holding this position excludes reliance on God’s goodness and mercy. Scholars who work in the area of Bible and related topics are often fixated on the kind of dogmatic consistency that seldom appears in real life: they think that people who believed in human effort and moral achievement must have renounced grace. Ancient Jewish groups, just like modern Jewish and Christian groups, had diverse religious thoughts and practices. To this day, when Jews or Christians pray to God, they thank him for calling them to follow him and for giving them the strength and ability to live as they should, and they recognize that in comparison to God humans are weak creatures who must rely on the strength and goodness of God. Yet when these same people falter, they do not blame God, they blame themselves. They seek to return to the path of righteousness, and they know that they must exert effort to do so. Humans are dependent on grace and they are accountable for their deeds. This is a common and in fact a virtually universal view in both Judaism and Christianity, and it is puzzling that many Christian scholars who accept both aspects of religion in their own lives believe that in the ancient world these were mutually exclusive alternatives. They are simply different perspectives that arise in slightly different circumstances. One set of thoughts arises in prayer or meditation, the other in considering the practicalities and difficulties of daily life. The two can combine in one sentence, as in this passage from the Hymns: ‘No man can be righteous in your judgment or [innocent] in your trial, though one man may be more righteous than another’ (1QH 9:14f.).
E P Sanders, The Dead Sea Sect and Other Jews: Commonalities, Overlaps and Differences in Lim, T. H., Hurtado, L. W., Auld, A. G., & Jack, A. M. (2004). The Dead Sea scrolls in their historical context. (31). London; New York: T&T Clark.