The Bible is very clear that we must test all prophecy. We are not to be naïve and gullibly believe that just because someone says they have a message from God it really is from God. On the other hand we must also be open to God speaking to us through prophecy and not have an overly skeptical or dismissive attitude:

1Thes 5:19-21
Do not put out the Spirit's fire; 20 do not treat prophecies with contempt. 21 Test everything. Hold on to the good.

I John 4:1
Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world.

You have three options when judging a prophecy:

• Reject the word
• Wait for confirmation on the word
• Receive the word.

In judging whether a prophecy really is from God we test three things:

• We test the message – does it line up with Scripture? Anything that contradicts the Bible should be rejected.
• We test the messenger – how godly and spiritually mature are they? If someone is living in sin, or seems like a fanatic, or is a new believer, you should be more cautious in receiving the word.
• We test the method – was it given in love and do you have peace? Prophecies given in a harsh condemning way or that shame and embarrass people are very unlikely to be from God.

It is also wise to take the prophecy to a spiritually mature believer, especially a Spirit-filled pastor who understands prophecy, and ask for their advice. This is especially true if the prophecy contains elements of correction or guidance.

Ultimately a prophecy is judged spiritually. Does it witness with your spirit? Does it seem right deep down inside? Does it seem like God is saying that it is right? When you pray about it does your spirit seem excited and free or are you knotted up in confusion and a feeling of dis-ease? Ultimately you must go with your gut-feeling. 

If you are still not sure whether the word is from God, wait for confirmation. The Holy Spirit will confirm with your spirit whether it is from God or give you further direction.