Spiritual truth, in particular, can only be apprehended by faith, not by any scientific method. That's the path to know God, beyond knowing about God through the evidence of the things He has created. An explorer who sincerely wants to learn about sea mammals doesn't start out denying that the sea is a thing and heading toward the forest. Likewise, advancing that nothing exists that has been created by God is intellectual dishonesty that stops the genuine pursuit of truth without giving the appearance of insincerity concerning such pursuit. It's elementary fact suppression to clear the way to assert that there is nothing that can be known or demonstrated about God. And from that follows the conclusion that God cannot be known or does not exist. But faith comes from what is heard about God.
What is heard about God is itself a testimony. Those who can testify that they know God will also hold true that He has communicated to mankind through a precise form: his word. The Bible is a record of God's communication to mankind through the writings of his servants. And He has laid out the precise way to approach Him:
"Therefore, putting away all filthiness and overflowing of wickedness [that's repentance], receive with humility the implanted word, which is able to save your souls. But be doers of the word [that's faith], and not only hearers, deluding your own selves. (James 1:21-22)
... "God resists the proud, but gives grace to the humble. Submit yourselves therefore to God. Resist the devil, and he will flee from you. Draw near to God, and He will draw near to you. Cleanse your hands, you sinners; and purify your hearts, you double-minded." (James 4:6-8)
"For the grace of God has appeared, bringing salvation to all people, instructing us to say “No” to ungodliness and worldly desires, and to live soberly, righteously, and godly in this present age; looking for the blessed hope and appearing of the glory of our great God and Savior, Jesus Christ; who gave Himself for us, that He might redeem us from all iniquity, and purify for Himself a people for his own possession, zealous for good works." (Titus 2:11-14)
... "God resists the proud, but gives grace to the humble. Submit yourselves therefore to God. Resist the devil, and he will flee from you. Draw near to God, and He will draw near to you. Cleanse your hands, you sinners; and purify your hearts, you double-minded." (James 4:6-8)
"For the grace of God has appeared, bringing salvation to all people, instructing us to say “No” to ungodliness and worldly desires, and to live soberly, righteously, and godly in this present age; looking for the blessed hope and appearing of the glory of our great God and Savior, Jesus Christ; who gave Himself for us, that He might redeem us from all iniquity, and purify for Himself a people for his own possession, zealous for good works." (Titus 2:11-14)
Humility is key in one’s approach to God (that's a personal trait rather than a scientific apparatus). That statement can be evaluated for its investigative worthiness. A truth-seeker should not simply accept any statement as true. That is not what faith is about. But carefully considering the thing heard is the path to have any kind of faith. That implies trusting the message-bearer or, at the least, giving him/her the benefit of the doubt. That will be the way to progress to what will be personal, irrefutable, evidence of God’s existence: knowing Him because He has been pleased to reveal Himself to you who sought Him on his terms, that is, according to his word.1
Jesus who is the Word of God that appeared in the world in the form of a man was seriously challenged for his claims while He walked on the earth. This can be learned from what is written about Him in the Bible. Jesus made this statement to people who had their doubts, as you may have yours about Him today: “My teaching is not mine, but his who sent me. If anyone desires to do his will, he will know about the teaching, whether it is from God, or if I am speaking from myself.”2 Thus, taking Jesus at his word is then a clear path to have proof that what He taught is true and not myths to add to the many that are already being propagated on the earth, even through formal education. And taking that route has its requirements.
A prerequisite to seeking to know the provenance of Jesus' teaching and what that would imply is the humility to recognize God’s sovereignty. And that’s already beyond the question of his existence. Hearing that God’s existence is being called into question is, for a servant of God, like being married and hearing the denials of others that one has a spouse or knows anything about the intimacy attached to having such a spousal relationship. Thus, coming to know God, there is a way to that; but needing to establish that He exists is not God’s concern for anyone who doesn't know Him yet.3
The attitude of a person who decides to approach God is therefore important. Jesus does refrain from revealing Himself to the random person who wants to check Him out. There is no seriousness in such an approach, while what He is looking for is a relationship like a marriage founded on love and faithfulness. The readiness to be in total submission to the King of kings cannot be excluded. Denominations do start by people who take the Christian name and embrace what they like about the teachings of Jesus or simply twist them. So, the truth must be sought, and it will be found by those loving it; it will save them.4 A good and honest heart is necessary to move forward.5 Therefore, when God opens the door for a relationship with Him, He expects reverence and that one offers to Him a heart that is ready to obey Him in all. That's a sacrifice. That's the real giving of one's life to God. And that's the only way to come to know God intimately - not unlike a husband knows his wife and vice versa. God will only come to be on the throne of one's heart where room has been made for Him in response to the way He has commanded that He should be approached: through repentance and faith in Jesus.
[You know] how I did not hold back from declaring to you anything that was profitable, and teaching you publicly and from house to house, testifying both to Jews and to Greeks repentance toward God, and faith toward our Lord Jesus Christ. (Acts 20:20-21)
2. John 7:16-17
3. Romans 1:19
4. John 8:31-36, 1 Timothy 2:1-5, 2 Thessalonians 2:8-12
5. Luke 8:8, 15
Note: This is not creative writing.
Revelation 12:11
They
overcame him by the blood of the Lamb, and by the word of their
testimony; and they did not love their life, even to death.