I understand that there are certain garments which Templetemple-going Mormons are obliged to wear after going through their initial Temple Ceremony. My question is regarding the basis for this. When did it originate? Was it a new revelation from God? Is it recorded in any LDS Scriptures or the Doctrines & Covenants? Does it have any relation to the priestly garments worn by Levites in the Old Testament?
I also understand that there are various symbols on them. What are the specific purposes of those?
I do not wish to be irreverent here. That would not be constructive, so please observe the same tone in any answers.