[Aquinasfan]

You have no problem referring to someone as the spawn of Satan?

"You may judge a tree by its fruit."

"He who is not with me is against me, and he who does not gather with me, scatters."

[Ward Smythe]

"You may judge a tree by its fruit."

And telling non-believers/scoffers that their father is Satan is going to produce fruit?

Some of those most violently opposed to God have become the strongest professors of the faith. I shudder to think what you would've said to Paul/Saul before his conversion.

But the fruit of the Spirit is love, joy, peace, longsuffering, gentleness, goodness, faith, meekness, temperance: against such there is no law.
Galations 5:22-23

Which one of those "fruits" fits with calling someone the son of Satan?