Tested Metal, Tested Mettle

“‘Be diligent to present yourself approved to God’ (v. 15, emphasis ours) As a young preacher, Timothy was exhorted to exert every effort to present himself to God as one approved. That term comes from the world of industry and coinage; it has to do with the testing of metals”

Olford, Anointed Expository Preaching, (p. 53).