What is a prophet? - a word study

A prophet proclaims a message given to him, thus is a spokesman for God speaking in God's name and authority. What the prophet says is not of man but of God.
The great task assigned to the prophets whom God raised up among the people was to correct moral and religious abuses to proclaim great moral and religious truths which are connected with the character of God.

However, scripture warns us in Mt 7:15 beware of false prophets that come to you in sheep's clothing.
Matthew Poole commentary - A false prophet is of the same significancy with a false teacher. Some of them indeed come in sheep’s clothing, under very fair pretences, and a fair show of religion and strictness; but they are ravening wolves, as dangerous to your souls as ravenous wolves are to a flock of sheep.
Jerome says “Beware of false prophets who come to you in sheep’s clothing, but inside they are ravenous wolves.” To be sure, this can be understood about all who promise one thing by their dress and speech, but who demonstrate something else by their deeds. But it should be understood particularly of the heretics. By their continence, chastity, and fasting, they appear to be wearing, as it were, a kind of garment of piety, but inwardly they have poisonous hearts, and they deceive the hearts of the simpler brothers. By the fruits of their soul, then, by which they entice innocence to its destruction, they are compared with ravenous wolves.

We need to sift the chaff from the wheat i.e the false from the truth which means we have to test what is said against the word of God.

Hope you enjoy this study and find the link to this study helpful.
https://docs.google.com/document/d/1ZksDyPyEzO03LSCgYziXlvv-HF4tEnsTwaPxpkWf_uY/edit?usp=sharing