For instance, seven days are set aside every year in which only unleavened bread may be eaten (vs. 6). This was a very important rule, the purpose of which was to serve as a reminder of the Exodus from Egypt when God delivered the Israelites. It is specifically mentioned that this is to be used to teach the next generations concerning God's strength and provision for His people.
Another touchstone is the rule concerning the firstborn of livestock and people. Every firstborn male animal (except donkeys) are to be sacrificed to the Lord. Donkeys are to redeemed (substituted) by a sheep; otherwise that animal is to be killed (vs. 13). We aren't given such an option when it comes to human firstborns. Every human infant must be redeemed by a sacrificial animal. Why? Again, this imperative is given for its value in instructing the children about God's deliverance of His people by killing all the firstborn in the land of Egypt (vs. 14).
Touchstones serve as a "sign on your hand and a reminder on your forehead" (vs. 9 and 16). They are educational devices to help us remember and teach.
We have touchstones in the Christian faith, in addition to these from our Old Testament background. Baptism and Communion serve as touchstones of our faith, re-enactments of crucial moments in the life and ministry of our Lord. Holidays, such as Christmas and Easter and Pentecost, provide opportunities of remembrance and celebration - as well as teaching and passing on of the fundamentals of our faith. Touchstones are what help give our faith structure, which can be healthy - as long as the importance of keeping tradition does not surpass the original meaning of God's grace.