“Little children, you are from God and have overcome them, for he who is in you is greater than he who is in the world. They are from the world; therefore they speak from the world, and the world listens to them. We are from God. Whoever knows God listens to us; whoever is not from God does not listen to us. By this we know the Spirit of truth and the spirit of error.” 1 John 4:1-6(ESV)
Spirit of God: John 10:27-39(ESV)
We are called sons and daughters of God who are with Jesus and follow Him. We should not waver in our beliefs. If we confess we are children of God we should test even our own spirits whether we are really believing and following all the commandments of Jesus. Because there are many false prophets, who have come up even among the believers, deviating people towards the worldly riches and pleasures. Jesus asked those who are following Him to deny themselves and take up the cross and follow Him. How many of us are doing that?
Spirit of Antichrist: Matthew 16:13-28(ESV)
You can see both the spirit of truth and the spirit of error operating in Peter which Jesus could discern and distinguish. This is what God wants us His children to do all the time so that we can be like Jesus and work with Him to give fruits that remain. One of the gifts of the Holy Spirit is discerning spirits. So let us practice and operate on that gift in us so that we are benefiting. The Antichrist spirit will not understand the Will of God or agree with it.
“For the mystery of lawlessness is already at work. Only he who now restrains it will do so until he is out of the way. And then the lawless one will be revealed, whom the Lord Jesus will kill with the breath of his mouth and bring to nothing by the appearance of his coming. The coming of the lawless one is by the activity of Satan with all power and false signs and wonders, and with all wicked deception for those who are perishing, because they refused to love the truth and so be saved. Therefore God sends them a strong delusion, so that they may believe what is false, in order that all may be condemned who did not believe the truth but had pleasure in unrighteousness.” 2 Thessalonians 2:7-12 (ESV)