Lyn posted a very good analysis on fasting on her Saved by Grace blog. I read the entire article by Gary Gilley. He makes some excellent points about where Pastor Piper goes wrong...but I really hoped he would touch on what Jesus said about demons and "prayer and fasting" but he never mentions it :(
Good article none the less, if we think we are getting direction from the Lord it always, always, ALWAYS needs to be checked with what the Bible actually says (and/or doesn't say), and must humbly turn back to the right way when shown the error of our ways. I hope that Pastor Piper and many of the others mentioned will realize they are holding to (and teaching) falsely and putting God's stamp on it. The most dangerous lies (and of course the devil knows this) are the ones that lead us gradually off course. God won't lose those who are His, but we can go through much unnecessary harm, and also bring harm (possibly prevent others from being saved? Not sure about that, but I personally do think that is possible, God warns us about false teachers, and Jesus tells the Pharisees that they prevent people from entering the kingdom and make them into devils)....So many lies and only one true way, let's be sure we stay on it by God's truth keeping us strong and keeping our feet on the right path:
Link to "Fasting and Direction"