Yahoshua said in Matthew 15:1-20 that uncleanness comes from within when the Pharisees questioned Him about His apostles not washing their hands. Yahoshua was talking about spiritual uncleanness. In Genesis 4:3-5 Abel gave Yah his best. Abel gave Yah the first of his flock (most likely his first sheep). But Cain picked up the dirty old fruit off the ground and gave it to Yah. He didn’t give Yah his best. Did he keep the best for himself? His offering was spiritually and physically unclean, unacceptable to Yah. I read in the Book of Jasher that Cain repents of his behaviors. First fruit, first of the flock.