God now defines the clean and unclean for Israel to consume with their bodies. These were defined so that God can give Israel blessings through the cleans food and to show them the path to righteousness is narrow. Now it is also narrow but in a different manner. Christ is the only way to God. He is the clean animal we are to consume (spiritually). The other things in this world, and the multitude listed as unclean, are not for us to enjoy or regard. Stay with the clean mission of Christ and overcome the unclean temptations we face daily through Him.
The actual clean and unclean is no longer directly relevant to us. Simon Peter has shown us all that the world is clean. Christ has lifted the limitations. Our duty now and fulfill the Word is to show the world how clean our hearts are with Christ at the center of them. Sin makes us unclean, Christ, through the Cross, washes away our sins. We are clean through Him always. Have faith in our Lord to lift us up and show us the Light, away from the darkness.