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.
With eternal knowledge, which includes eternity past all through eternity future, the Lord Jesus can judge with perfection what to fear. Jesus says that we should fear the one who can destroy body and soul more than the one who can destroy just body. The detection of that which can destroy both body and soul in hell forever is far more important than the one who can destroy just body. With this contrast Jesus reveals the truth about the priority of detecting and correcting doctrinal and practical error. Even though people do not treat it as such, there is so much more at stake with it.
People stress personal protective equipment. When the virus first started its spread, there was a shortage on this, and it was a big deal to have it for obvious reasons. It was very important to protect people. The virus kills. But it only kills body. Doctrinal error specially, which is also practical, is more important to detect and stop or correct. Much doctrinal error and a diverse, large variety of it, is enough at least to destroy both body and soul in hell forever. Forever. This is very serious. If Jesus says it is this serious, it is this serious. Destruction of body and soul forever blows away mere destruction of body. Jesus said in Mark 9:47 it would be better to pluck out your eye and enter into the kingdom than having two eyes to be cast into hell fire.
False teachers (Matthew 7:15) are the first reason people take the broad road to destruction. They aren't pointing to the narrow road with their false teaching, but to the broad road that leads to destruction (Matthew 7:13-14). Jesus says they're wolves in sheep's clothing and they want to destroy sheep, obviously by destroying their souls with all sorts of what 2 Peter 2:1 calls, "damnable heresies." Jude 1:11 calls this destruction of the soul, perishing in the gainsaying of Korah, which in the next chapter of 2 Peter (3:17), Peter speaks of those who will fall from their steadfastness, being led away with the error of the wicked.
Those who save those from the damnable teaching of false teachers, James says convert from the error of their way and save their souls from death (5:20). Paul says in 1 Timothy 4:16 says that by taking heed unto true doctrine, they will save themselves and those who hear them. Those who abide not in the doctrine of Christ, John says they have not God (2 John 1:9). In some cases, believers are deceived through the false teaching of false prophets, which is enough to distract them from service or at least effective service (1 Cor 15:33, Col 2:9).
The detection and correction of doctrinal and practical error has eternal ramifications for the souls of men. An error in need of detection and correction from the onset is one of proportion, when the fear of him who can destroy only body extinguishes or overshadows the fear of Him Who can destroy both body and soul in hell forever.