פירוש על מגילה 51:2

If they sold...: One elevates in sanctity and does not downgrade."one elevates in sanctity" as it is written: "Moses set up the Tabernacle" (Shemot 40:18) - Bezalel made it and Moses who was greater than he set it up. "...and doesn't downgrade" as it is written: "...the firepans of those who sinned at the cost of their lives and let them be made into hammered sheets as plating for the altar - for once they have been used for offering to the Lord, the have become sacred..." (Bemidbar 17:3). Because they were sanctified they (remained) sanctified.