Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world.
You, dear children, are from God and have overcome them, because the one who is in you is greater than the one who is in the world. They are from the world and therefore speak from the viewpoint of the world, and the world listens to them. We are from God, and whoever knows God listens to us; but whoever is not from God does not listen to us. This is how we recognize the Spirit a of truth and the spirit of falsehood.
– 1 John 4:1-6
I could quote the entire Bible, but wouldn’t it be better to simply point you in the direction of the Bible? I use two resources.
The first one is Bible Gateway, which has dozens of different versions, all free, all online, through the same powerful search engine. I always use the NIV, as it’s considered the most grammatically correct version in the English language (bumped my English stanines 12% by reading it), and is highly rated among all normally translated versions make up the pack.
The second one is the Interlinear Bible, which is a direct word-for-word translation from the ancient texts, complete with linked Strong’s Concordance, linked cross-references in the Latin, the original Hebrew or Greek, English, and speech parts/person/tense/voice/case/number/gender/comparison. Because it’s word-for-word, the order of the words is wonky to English-speakers, but the translation is, word-for-word, more accurate. Example: “Beloved not every spirit believe but test the spirits…” – 1 John 4:1.