If You Don't Believe Existence of Spirit...
Spirit or the Holy Ghost is one of key concepts in the Gospels:
Luke 316 John answered, saying unto them all, I indeed baptize you with water; but one mightier than I cometh, the latchet of whose shoes I am not worthy to unloose: he shall baptize you with the Holy Ghost and with fire:21 Now when all the people were baptized, it came to pass, that Jesus also being baptized, and praying, the heaven was opened,22 And the Holy Ghost descended in a bodily shape like a dove upon him, and a voice came from heaven, which said, Thou art my beloved Son; in thee I am well pleased.Luke 413 And when the devil had ended all the temptation, he departed from him for a season.14 And Jesus returned in the power of the Spirit into Galilee: and there went out a fame of him through all the region round about.John 132 And John bare record, saying, I saw the Spirit descending from heaven like a dove, and it abode upon him.
33 And I knew him not: but he that sent me to baptize with water, the same said unto me, Upon whom thou shalt see the Spirit descending, and remaining on him, the same is he which baptizeth with the Holy Ghost.
John 3
5 Jesus 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.
6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
7 Marvel not that I said unto thee, Ye must be born again.
8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
So, to believe in Christ Jesus, the Gospels, and the Bible is to believe in existence of Spirit or the Holy Ghost as well as Heaven and the hell.
This world is made of material or substance, but one is also made of a mind connected to a soul or a spirt. In addition, Plato claimed that there is the world of ideas or perfect representations of concepts.
In this context, it should be noted that some wise men say that there are visible elements and non-visible elements in this world. Even the modern physics handles dark matter and dark energy that are not observed.
Although the modern science cannot scientifically fully explain how this universe was generated, it seems reasonable that a certain type of energy in the spirit world caused the generation of this physical universe.
Likewise, although the modern science cannot scientifically fully explain how a mind or consciousness is generated in the human brain, it seems reasonable that a certain type of energy in the spirit world causes the generation of a mind, consciousness, or an inner psychological world in the human brain.
Rather, we should think that the spirit world is the real world and this material universe is a kind of secondary world; the God, spirits, and angels are essential and real but this material world is a kind of secondary world; or Plato's world with perfectness is principal and this human world is subsidiary.
Anyway if you don't believe existence of spirit or a soul above your mind, you cannot even imagine or understand the God. You may as well doubt the existence of your mind.
++++ ++++ ++++
John 7, King James Version
11 Then the Jews sought him at the feast, and said, Where is he?
12 And there was much murmuring among the people concerning him: for some said, He is a good man: others said, Nay; but he deceiveth the people.
13 Howbeit no man spake openly of him for fear of the Jews.
14 Now about the midst of the feast Jesus went up into the temple, and taught.