The action of the man was in doing what God told him to do. The faith was what led him to do so.
He believed that God would raise Isaac from the dead.
Where do you get this from?
SD
Although I'm not totally onboard with Mack downplaying the "works" aspect of the faith/works paradox, I'll tell you where he gets it from.
Hebrews 11:17 By faith Abraham, when he was tried, offered up Isaac: and he that had received the promises offered up his only begotten son, 18 Of whom it was said, That in Isaac shall thy seed be called: 19 Accounting that God was able to raise him up, even from the dead; from whence also he received him in a figure.