http://www.remnantofgod.org/Trueprophets.htm
If you read at the bottom of the link that even false prophets can perform miracles too!
They forgot to mention this, it is written:And he doeth great wonders, so that he maketh fire come down from heaven on the earth in the sight of men, And deceiveth them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live. Revelation 13:13,14
Just watch television and watch some of these great faith healers perform false miracles, How can you tell if their real or not?
Jesus said that it would be very difficult to tell especially in the last days, listen to their teachings, do they follow exactly what is written in the bible?
It is written: 2 Timothy 2:15 - Study to shew thyself approved unto God, a workman that needeth not to be ashamed, rightly dividing the word of truth.
God Bless!