"And many false prophets will arise and lead many astray." Matthew 24:11
"Now the Spirit expressly says that in later times some will depart from the faith by devoting themselves to deceitful spirits and teachings of demons," 1 Timothy 4:1
"For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions, and will turn away from listening to the truth and wander off into myths." 2 Timothy 4:3-4
I don't think there's a whole lot of doubt that there are a lot of false religions floating around. But what about when a professing "Christian" is teaching heresy and leading believers astray? Jesus warned us that, in the later times, these false teachers would be even more abundant. Be discerning, test their teachings against God's Word. But even moreso, don't be content to allow others to blindly follow these people. Be the watchman and warn them, so that they don't end up spending eternity with their heretical leader in the lake of fire. Take a stand, open your mouth, and don't let these "goat herders" get away with staining the name and message of Christ.
One of the biggest dangers to the church today is the Emergent Church Movement. Beware of these teachings--they preach heresy wrapped in a box tagged "Christian"!
A great editorial that mirrors my feelings about the Emergent Church and false prophets like "pastor" Rick Warren...