I learned this from a Christian business woman who was approached by 2 men who were Christians with a business deal. Everything seemed right, but in the end the deal turned out to be a scam. She asked the Lord why she had not seen this coming, and the Lord taught her about testing the spirits.
1 John 4:1-3 “Beloved, do not believe every spirit, but test the spirits to see whether they are of God; for many false prophets have gone out into the world. By this you know the Spirit of God: every spirit which confesses that Jesus Christ has come in the flesh is of God, and every spirit which does not confess Jesus is not of God. This is the spirit of antichrist, of which you heard that it was coming, and now it is in the world already.”
1 John 5:6-8 “This is he who came by water and blood, Jesus Christ, not with the water only but with the water and the blood. And the Spirit is the witness, because the Spirit is the truth. There are three witnesses, the Spirit, the water, and the blood; and these three agree.”