Leviticus 11:44 (NKJV)
For I am the Lord your God. You shall therefore consecrate yourselves, and you shall be holy; for I am holy. Neither shall you defile yourselves with any creeping thing that creeps on the earth.
God gives the Israelites instructions regarding what is clean and unclean. Animals with split hooves and who chew the cud are clean while others are not. It seems so strange. While we can see obvious health benefits for some of these laws, others have no rational basis.
In the above verse God tells us what is going on. We are to be holy because he is holy. To be holy means to be set apart. Obedience to such detailed practices set God's people apart. God's people are to live differently from everyone else. We don't obey God because it makes sense. We obey God because he is God and has instructed us and we must be holy people of God, obedient to his every command.
1 Peter 2:9-10 (NKJV)
But you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light; who once were not a people but are now the people of God, who had not obtained mercy but now have obtained mercy.