James 5:3

3. Gold… cankered Literally, rusted. Gold, however, never does truly rust, or oxidize, just as fire does not eat, or rust eat flesh. Such a fact is, of course, here only figured, as an image of the perishability of human fortunes. Bloomfield says, “Gold does not, properly, rust; yet by long use it contracts a green colour, and a sort of acid humour. The ancient gold and silver might be more liable to rust, from having a greater proportion of alloy.” That greening of gold coin was viewed as a sort of rust, as appears from the poet Theocritus, (Idyl 16,) where he says that no one would give poets money; nay, “not rub off the rust of their money and give it to them.”

Witness against you Not against, but to, you. It does not testify to any crime, but prophesies that you shall be even cankered as it is.

For the last days Literally, in last days. It is to be noted that the heaping of the treasure was within, not previous to, the last days. Both last days and day of slaughter are without the Greek article, while coming, of James 5:7, (where see note,) has the article. Both these terms, last days and day, clearly signify the closing days of the apostolic age of the Church, coincident with the closing days of the Jewish State. See notes on 2 Thessalonians 2:7; 1 Timothy 4:1; 2 Peter 3:3; 1 John 2:18-22; 1Jn 4:3 ; 2 John 1:7.