Knowing the source of prophesy
I believe we can know the source of a Prophetic Word we are to share before we even open our mouth. There are three sources from which prophecy can come. They are:
1. GOD THE HOLY SPIRIT:True, general prophecy will always come in the framework of edification, exhortation and comfort. It is given in the spirit of love and seeks to build up rather than condemn or knock down. One needs to ask oneself before prophesying: "Does this message build the people up according to the Scriptural guidelines? Does it glorify Jesus Christ?" If you can answer "yes" to those questions, then your word is of God. Bring it forth in the inspiration of the Holy Spirit.
2. THE SPIRIT OF MAN:Prophecy that is "inspired" by the spirit of man does not edify, exhort or comfort. It is negative and critical, often presented with an Old Testament style threat of judgement if the hearers don't obey. We have every right to reject that kind of prophecy.
3. SATANIC: Satanically-inspired prophecy is subtle, deceptive, manipulative, domineering and the opposite to the character and nature of God. It does not edify, exhort or comfort the believer to get closer to Jesus Christ, but can manipulate people to make major decisions hastily, thus causing wrong decisions that take us out of the will of God. It can be "cold, heavy and condemnatory," but also like "an angel of light" (2 Corinthians 11:14). Satan will try and hide his true nature in the delivery of such. We need to use the Gift of Discerning of Spirits so we can not only reject such prophecies but also warn others against them when they come.
How do we prophesy?
When that Word of Prophecy comes, it first comes into our spirit; then very quickly to our mind where we understand the content of the message (the theme, words, etc.). The anointing confirms we have "a word" to bring and therefore we look for the right opportunity to share it publicly or individually