Assumng you mean prophets of Adonai (God) and not just the false prophest of, say, Baal and that lot ... one has the true backing of God and all the others are calling on demons, false gods or thin air.. . All can tell the future. However, Psychics and mediums draw on satanic power for their visionary abilities (and are condemned in Scripture for so doing) whilst the Godly prophet is authorised to speak on behalf of God.. . The other difference of course, is that God never lies, whilst Satan is the father of lies, so make your own conclsions.