In many ways 1John answers most of the question anyone can have in regards to how someone who is One with God and Christ is to act, behave and how the spirit works through them, some examples are:
13 By this we know that we abide in him and he in us, because he has given us of his Spirit. 14 And we have seen and do testify that the Father has sent his Son as the Savior of the world. 15 God abides in those who confess that Jesus is the Son of God, and they abide in God. 16 So we have known and believe the love that God has for us.
God is love, and those who abide in love abide in God, and God abides in them. 17 Love has been perfected among us in this: that we may have boldness on the day of judgment, because as he is, so are we in this world. 18 There is no fear in love, but perfect love casts out fear; for fear has to do with punishment, and whoever fears has not reached perfection in love. 19 We love b because he first loved us. 20 Those who say, “I love God,” and hate their brothers or sisters, c are liars; for those who do not love a brother or sister d whom they have seen, cannot love God whom they have not seen. 21 The commandment we have from him is this: those who love God must love their brothers and sisters e also.
4 Beloved, do not believe every spirit, but test the spirits to see whether they are from God; for many false prophets have gone out into the world. 2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God, 3 and every spirit that does not confess Jesus a is not from God. And this is the spirit of the antichrist, of which you have heard that it is coming; and now it is already in the world. 4 Little children, you are from God, and have conquered them; for the one who is in you is greater than the one who is in the world. 5 They are from the world; therefore what they say is from the world, and the world listens to them. 6 We are from God. Whoever knows God listens to us, and whoever is not from God does not listen to us. From this we know the spirit of truth and the spirit of error.
And there are mor ein the the various writings of the apostles.
They key is that IF a person is in communication with God then LOVE is the message they will bring.
If one hears voices that are telling one to harm, to lie, to cheat, to steal, to harm others, to hate and to be intolerant, then the voice is Not of God.
Another clue is that one does NO hear voiceS, one hears A voice, THE voice and it is like "coming home".