Because of false prophets and teachers, we must not believe every spirit but test if they are of God. The test is this: do they teach Jesus Christ was the Son of God in the flesh? Jesus was more than a teacher and greater than a prophet. He was not just a good man but is God incarnate.
God is love according to this text but that truth must be understood in context. Otherwise that statement can be wrongly used to justify all types of sin. That’s a good example of discerning the Spirit of God from the spirit of antichrist.