James 5:3

Verse 3 Your gold and silver is cankered.

That is, the gold and silver they had treasured up had contracted rust, for they are in fact herein charged with having been engaged for a long period of time in hoarding this kind of treasure. Observe that it is not the use of these metals, but the non-use of the same, for which they are censured. The rust in this case is supposed to come from the failure to use. This failure to use showed beyond question that the proper use had not been observed, or, in other words, that the legitimate design of gold and silver, by its being hoarded, had not been accomplished. The employment of gold and silver in acts of beneficence would have prevented the rust. The unjust and wicked amassing from the love of such riches was covetous was wrong. The rust accumulated on such hoarded treasure was itself a witness against those so hoarding it, and will eat their bodies as a fire. The conscience being irritated, your hoarded treasure is a curse to you.

Ye have heaped treasure together for the last days.

Another allusion to the coming destruction of Jerusalem. Suppose the accumulation to be immense, and yet all is lost in the general destruction, what avails it? What have you accomplished by your toil and labor? Absolutely nothing. You Jewish Christians, if you are so engaged, you make a great blunder. The author of the Christian faith gave explicit warning concerning these last days and the miseries that should follow. Your treasures will, like a bird, fly away, and you will be left destitute. Your time is wasted and you have failed to lay up treasures in heaven, as your plain duty was, Sand as you were so plainly and yet so tenderly admonished.