Even verses, even short passages, even chapters, even individual books are sufficient to bring people to faith in Jesus Christ, as was the Ethiopian. (I once met a man who said he came to faith in Jesus Christ by reading the book of Job.) I am sure some people have come to faith through less than perfect translations into indigenous languages. The inspired Word and the work of the Holy Spirit make whatever we may have of the written revelation of God sufficient for our needs.
You might ask why if a little bit of Scripture is sufficient for redemption there is so much of it in the Bible. Here I think we need to go back to the idea of Scripture being a creation of the Holy Spirit. Like physical creation the Bible has depth beyond the understanding of any single human mind and in its total richness is deeper than the collective mind of humanity is able to understand.
This is the other side of sufficiency. You may have noticed that serious Bible commentaries take up a good part of a bookshelf or even more. This is because the immense content of the Bible is sufficient to provide material for endless study for even the most diligent Bible scholar. The Scriptures are, I believe, a well of wisdom that never goes dry.