John Calvin Commentary James 1:8

"a doubleminded man, unstable in all his ways." — James 1:8 (ASV)

A double-minded man, or, a man of a double mind. This sentence may be read by itself, as he speaks generally of hypocrites.

However, it seems to me that it is rather the conclusion of the preceding doctrine. Thus, there is an implied contrast between the simplicity or liberality of God (mentioned before) and the double-mindedness of man. For as God gives to us with an outstretched hand, so it is fitting for us, in turn, to open the bosom of our heart.

He then says that the unbelieving, who have devious and hidden inner workings, are unstable; because they are never firm or fixed, but at one time they swell with the confidence of the flesh, and at another, they sink into the depths of despair.