I fear you do not understand what relics are or the purpose of Scripture. I do not brush the matter aside, I say there is no Scriptural justification for Christians to concern themselves with relics and much reason not to.
The very purpose of the Ark of the Covenant, which we read about in Scripture, was to carry about “relics” because they were historical evidence of God intervention in the lives of his people. The purpose of Scripture is to relate sacred history, so that we might know Him.