About 15 years ago a few of us were big style into John MacArthur and to this day we would all agree that his sermon on knowing God's will was a pivotal moment in our lives. Of course we've all grown and would probably have extra things to add to it but for me, and others i know, it is probably the no1 most influential & helpful sermons we've heard.
Here's an amazing thing i only noticed today - John MacArthur preached this sermon in 1972 (6 years before i was even born).
http://www.gty.org/resources/sermons/1217/how-to-know-the-will-of-god
I'd have to add John Piper's message Boasting Only In The Cross Of Christ as another that, hugely impacted me back in my young Christian days and has still ripples running through the pool of my life.
http://www.desiringgod.org/conference-messages/boasting-only-in-the-cross
What Sermons have helped you over the years - what stands out among all the others you've listened?
