http://www.jw.org/download/?fileformat=PDF&issue=20131215&output=html&pub=w&langwritten=E
Here's one extract:
9. Why should we be on guard if someone begins to speculate or to speak critically?
9 We are nearing the outbreak of the great tribulation and the end of this wicked system, so those inspired warnings given in the first century take on greater significance. We definitely do not want to ‘miss the purpose’ of Jehovah’s undeserved kindness and lose out on the promise of everlasting life, be that in heaven or on earth. (2 Cor. 6:1) If ever someone attending our congregation meetings would try to entice us into discussions of personal speculations or critical conversations, we should definitely be on guard.—2 Thess. 3:13-15.
http://www.jw.org/en/publications/magazines/w20131215/avoid-being-shaken-from-reason/