You have confused several worldly (including theological) definitions with what God plainly says:
THE LORD KEEPS IT SIMPLE
"And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell." --Matthew 10:28
He says nothing of a threat--that would be absurd--for only people or animals are reduced to making threats: God speaks reality into being, so when He says I'm gonna destroy you, and in a horrible way, then that's just what's gonna happen, period. Moreover, God is not dangerous, people and animals are, but God is not: He is sovereign, the only true sovereign in existence, thus, He is dreadful. And lastly, if pain is the concern, then you've greatly misunderstood, for God is not talking about hurting those who hate Him, but destroying them, shamefully, and utterly--the horrible pain ought to be the least of your concerns, for it is the destruction that remains, not the pain.
The case of the Jewish young men, who obeyed the Lord not to fear man, but God, is a great example that quickly illustrates the point:
SHADRACH, MESHACH, AND ABED-NEGO
"Then Nebuchadnezzar in his rage and fury commanded to bring Shadrach, Meshach, and Abed–nego. Then they brought these men before the king. Nebuchadnezzar spake and said unto them, Is it true, O Shadrach, Meshach, and Abed–nego, do not ye serve my gods, nor worship the golden image which I have set up? Now if ye be ready that at what time ye hear the sound of the cornet, flute, harp, sackbut, psaltery, and dulcimer, and all kinds of musick, ye fall down and worship the image which I have made; well: but if ye worship not, ye shall be cast the same hour into the midst of a burning fiery furnace; and who is that God that shall deliver you out of my hands? Shadrach, Meshach, and Abed–nego, answered and said to the king, O Nebuchadnezzar, we are not careful to answer thee in this matter. If it be so, our God whom we serve is able to deliver us from the burning fiery furnace, and he will deliver us out of thine hand, O king. But if not, be it known unto thee, O king, that we will not serve thy gods, nor worship the golden image which thou hast set up." --Daniel 3:13-18
Fear God, therefore, in the way He commands; only then will you begin to understand.