"I speak as to wise men; judge for yourselves what I say."
1 Corinthians 10:15 (NKJV)
"Let two or three prophets speak, and let the others judge."
1 Corinthians 14:29 (NKJV)
Thirdly, it is right for the Church to judge the doctrinal teaching of preachers/prophets.
Remember I said that we are not to judge ministry style but we are to judge ministry content. However, this only extends as far as we have the God-given authority to judge. If the ministry is not in our own local Church we are to discern if their teaching is right or not but we do not have the right to publically judge and criticize them. If we are a Church leader we can warn those under our authority about this false ministry but we should leave it at that.
If a false ministry arises within a Church or Denomination then the leaders of that Church or Denomination have the right and should judge and cut off that ministry if necessary. There are many so-called "Discernment Ministries" on the internet I have seen bombarding all types of ministries they feel are heretical (most times they attack their ministry style not content). In these cases they do not have the moral authority to do so. Even if they are warning other Christians they should only warn those under their immediate authority, not the whole world through the internet!
When done properly, this judgment saves Churches and Christians from being deceived and entering into error. In our Church we used to be very laid back about inviting guest speakers until we had an unfortunate encounter where a preacher came and taught heresy with a very proud and rebellious spirit. After that we have been very careful who we invite, checking up on their ministry track record and doctrinal beliefs, usually needing strong personal references.
What this means for the individual Christian is that we must be like the Bereans, checking out from Scripture to see if what we hear from the pulpit is truly Scriptural. If it is not we can only publically judge if we are in the place of authority to do so. If not we must guard our hearts, refraining from back biting and making sure we distance ourselves from such error and warn those we should about the ministry in question.
Lord, let Your Word dwell in me richly,
So I may tell when falsehood comes.
That I may judge with righteous judgment
Warning my sheep so that none succumbs.
"Father, help me discern properly between the truth and false teaching and help me judge righteously according to the moral authority You have given me. Amen!"