3Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
4Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
5Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.
6That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
You see there's a new birth that takes place when we are saved. It is not a physical birth, as when you were born into the world - but a spiritual birth. You must receive this birth, or you will continue to walk according to the flesh.
1 John 2:15-17
15Love not the world, neither the things that are in the world. If any man love the world, the love of the Father is not in him.
16For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.
17And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.
So then, how do we know that we have been born again? We know that if we walk according to the lust of the flesh, that the father is not in us. But if we walk according to the will of God, we abideth for ever.
16This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.
17For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.
18But if ye be led of the Spirit, ye are not under the law.
19Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness,
20Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies,
21Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
You can see that we need the spirit of God, if we want to be led my the spirit. If you would like to be led by the spirit of God today, cry out to him and ask him to come into your heart.
6In my distress I called upon the LORD, and cried unto my God: he heard my voice out of his temple, and my cry came before him, even into his ears.