Here is an example: Christians should accept with veneration these writings, which give expression to a lively sence of God, which are a storehouse of sublime teaching on God, of sound wisdom on human life, as well as a wonderful treasury of prayers; in them, too, the mysterious of salvation is present in a hidden way. -----In this stence, i am wondering "as well as a wonderful treasury of prayers" , anything omitted before it?and also the last sub sentence " in them..." confused me.

Probably grammar. Could you provide an example?