This statement in Alma 7:21 reminds me of the great qualities that King Benjamin talked about in Mosiah 3:19, in saying that "the natural man is an enemy to God, and has been since the Fall of Adam, and will be forever and ever until he yields to the enticing of the Holy Spirit and becometh a saint through the atonement." The natural conditions of wickedness include "filthiness" which cannot be received into the kingdom of God. Being pure and clean would not have been a common daily occurrence for most of these people, who did not have bathtubs or showers in their homes.
Some of the things that Benjamin lists in Mosiah 3:19 are repeated here by Alma in this passage: humble, submissive, gentle, patient, long-suffering and being easy to be entreated (7:23). It is interesting to me that patience is included here. Patience is included in Alma 9:26 where Alma talked about the characteristics of the Savior. We don’t often think of how patient God is with us, as He puts up with us despite all that we do. What in your mind makes patience such a Godly virtue?