The Bible makes quite clear that, if we seek the truth about God, we must be willing to embrace that truth.
Mere idle curiosity is not an option since God will either aid or hinder or even completely block our efforts depending on our attitude.
Christ expands on this making clear that both attitudes and desires within us and beings outside us can inhibit or even prevent our learning. In the parable of the sower, Christ explains that many who do here -- at least momentarily -- abandon what they've learned because of difficulties in life, or because Christianity interferes with their desires or ambitions, or because Satan or demons somehow remove what has been learned.
Ironically, even the parable itself is an obstacle, since it obscures the truth from the unwilling.
Indeed, the Bible gives us a picture of a God who both wants us to know about Him, and to have a relationship with Him . . . but also a God who will not give us endless '2nd chances' -- if we choose to reject Him, it make become impossible for us to change our minds.
Therefore, as the Holy Spirit says, “Today, if you hear his voice, do not harden your hearts as in the rebellion -- Hebrews 3:7,8
And he told them many things in parables, saying: “A sower went out to sow. And as he sowed, some seeds fell along the path, and the birds came and devoured them. Other seeds fell on rocky ground, where they did not have much soil, and immediately they sprang up, since they had no depth of soil, but when the sun rose they were scorched. And since they had no root, they withered away. Other seeds fell among thorns, and the thorns grew up and choked them. -- Matthew 13:3-7
This is why I speak to them in parables, because seeing they do not see, and hearing they do not hear, nor do they understand. -- Matthew 13:13
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But I will harden Pharaoh’s heart, and though I multiply my signs and wonders in the land of Egypt, Pharaoh will not listen to you. -- Exodus 7:3,4
O LORD, why do you make us wander from your ways and harden our heart, so that we fear you not? -- Isaiah 63:17
But, what is it that we should know?
It can't be all the truth, since we lack minds capable of knowing all the truth about anything, much less everything. Nor can we even hope to know all the truths, or facts, about everything that humans collectively know, since we aren't even capable of that . . . no matter how smart we think we are.
So, what, then? CS Lewis provided the answer, I think.
In his book, "Mere Christianity", where he wrote that he felt it his calling to "to explain and defend the belief that has been common to nearly all Christians at all times.". The name he gave this approach was borrowed from Richard Baxter, a 17th Century Anglican cleric.
We need to know -- and embrace -- those truths known to all Christians, everywhere, and always.
Knowing these things is possible . . . and for Christians . . . essential.
“I am a CHRISTIAN, a MEER CHRISTIAN, of no other Religion; and the Church that I am of is the Christian Church, and hath been visible where ever the Christian Religion and Church hath been visible: But must you know what Sect or Party I am of? I am against all Sects and dividing Parties: But if any will call Meer Christians by the name of a Party, because they take up with Meer Chrisitanity, Creed, and Scripture, and will not be of any dividing or contentious Sect, I am of that Party which is so against Parties: If the Name CHRISTIAN be not enough, call me a CATHOLICK CHRISTIAN; not as that word signifieth an hereticating majority of Bishops, but as it signifieth one that hath no Religion, but that which by Christ and the Apostles was left to the Catholick Church, or the Body of Jesus Christ on Earth.”
-from Richard Baxter’s Church-history of the Government of Bishops (1680) [quoted from https://www.discovery.org/a/460/ ]
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But for better or worse, Lewis never spelled out just what the boundaries of this "belief".
And yet, it seems that it may not be that difficult to do so.
Jesus Himself taught that the 2 Great Commands -- understood and followed rightly -- include the 10 Commands.
And He gives the Lord's Prayer, both as an actual prayer AND as an example or paradigm showing us HOW to pray.
The 2 Great Commands, the 10 Commands, and the Lord's Prayer cover a LOT of ground in telling us how to behave.
Few, if any, churches reject these things.
What church will overtly teach Christians to hate God, or their neighbor? Or to steal or murder? Or to gossip or give false testimony? Or to worship something besides God?
It is true that many churches affirm these principles in theory, but then ignore them in practice. There is nothing new about that, and hypocritical behavior does not invalidate correct teaching.. Christ told his disciples to listen to the Pharisees but to ignore their example, because they were dishonest hypocrites, even though they often did teach what the Scriptures said!
So, what is being taught?
In this day, it may be hard to see clearly, because words like "love" have been so abused that they rarely mean anything Biblical.
Still, the Commands are -- mostly -- not that hard to understand:
Recognize that God made you and everything else, and has the right to do with ANYTHING He made ANYTHING He wishes.
In practice, don't put anything in the place of God -- not money, not icons, not images, not career, not pleasure, not ANYTHING.
Speak about God ONLY in ways that accurately and honestly reflect who He is.
The Sabbath . . . well, this one is both difficult and controversial. For now, set aside some time, regularly, each week to acknowledge that everything good in your life comes from God, and is NOT something He owes you. Almost all churches agree with at least that much.
A bit controversial, too. But basically, almost all churches agree that God has placed authorities in your life -- parents, teachers, bosses, government officials -- and trust Him to control their actions. This does not mean you should obey when they command that YOU do something contrary to the other commands, and it doesn't mean that you must obey when they give orders outside their realm of authority.
Don't kill anyone who God has not given you the right to kill.
(Some churches say that, in this day, you have no right to kill anyone, even in self-defense. Others allow self-defense and participation in just policing or wars.)
Don't have sex with ANYONE who God has not given to you in legitimate marriage.
(This is a difficult area. Many churches have tolerated both divorce and fornication -- sex between unmarried people -- in a hypocritical, Pharisaical way. But, when push comes to shove, almost all churches agree that sexual relations should occur in heterosexual marriage . . . and nowhere else. A few have claimed that homosexual marriages can be legitimate. But even though they DO it, no one claims that careless divorce OR fornication (hetero OR homo) is anything but sin. )
Don't take anything from anyone else, unless God has given it to you.
(Stealing is the illegitimate taking of property: you can take money, by legal force, from someone who has injured you, and this is not forbidden. But you can't take anything you have no specific right to take . . . even if you are hungry or poor! On the other hand, if you HAVE an abundance, and you have starving neighbors, JESUS teaches that YOU are stealing from God, by not giving to their needs!)
The 2 Great Commands
"36 “Teacher, which is the great commandment in the Law?” 37 And he said to him, “You shall love the Lord your God with all your heart and with all your soul and with all your mind. 38 This is the great and first commandment. 39 And a second is like it: You shall love your neighbor as yourself. 40 On these two commandments depend all the Law and the Prophets.” Matthew 22:36
Listen, but don't follow their examples!
Then Jesus said to the crowds and to his disciples, “The scribes and the Pharisees sit on Moses’ seat, so do and observe whatever they tell you, but not the works they do. For they preach, but do not practice."
Matthew 23:1-4
The 10 Commands
"6 “‘I am the LORD your God, who brought you out of the land of Egypt, out of the house of slavery. 7 “‘You shall have no other gods before me.
8 “‘You shall not make for yourself a carved image, or any likeness of anything that is in heaven above, or that is on the earth beneath, or that is in the water under the earth. 9 You shall not bow down to them or serve them
11 “‘You shall not take the name of the LORD your God in vain.
12 “‘Observe the Sabbath day, to keep it holy, as the LORD your God commanded you. 13 Six days you shall labor and do all your work, 14 but ethe seventh day is a Sabbath to the LORD your God. On it you shall not do any work, you or your son or your daughter or your male servant or your female servant, or your ox or your donkey or any of your livestock, or the sojourner who is within your gates, fthat your male servant and your female servant may rest as well as you.
16 “‘Honor your father and your mother, as the LORD your God commanded you, that your days may be long, and that it may go well with you in the land that the LORD your God is giving you.
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17 “‘You shall not murder.
18 “‘And you shall not commit adultery.
19 “‘And you shall not steal.
20 “‘And you shall not bear false witness against your neighbor.
21 “‘And you shall not covet your neighbor’s wife. And you shall not desire your neighbor’s house, his field, or his male servant, or his female servant, his ox, or his donkey, or anything that is your neighbor’s.’" Deuteronomy 5:6-21
The Lord's Prayer
"Pray then like this:
“Our Father in heaven, hallowed be your name.
10 Your kingdom come, your will be done,2
on earth as it is in heaven.
11 Give us this day our daily bread,12 and forgive us our debts, as we also have forgiven our debtors.
13 And lead us not into temptation, but deliver us from evil.
14 For if you forgive others their trespasses, your heavenly Father will also forgive you, 15 but if you do not forgive others their trespasses, neither will your Father forgive your trespasses." Matthew 6:9-15
The Summation
the one who loves another has fulfilled the law. 9 For the commandments, “You shall not commit adultery, You shall not murder, You shall not steal, You shall not covet,” and any other commandment, are summed up in this word: “You shall love your neighbor as yourself". Romans 13:8
the Pauline doxologies and compact creeds and the primary ecumenical creeds, the Apostles' and the Nicene creeds seem to be the right place to start: since hardly any church denies what is taught by any of these . . . even if they claim "No creed but Christ!".