Why Do Religions Believe In God?

God possesses absolute purity, free from even the slightest hint of wrongdoing in His nature. The Holy Creator is the source of honesty, patience, purity, holiness, love, and much more, and this is reflected in the way He designed our world.

Do I Have To Believe In God?

God wants us to live our lives in a certain way because that's who He is, not just to give us a hard time. He is forever consigned to his current condition. God won't act in a way that contradicts His own identity.
Think of it as the enduring principles that guide the universe.
The God spoken of in the Bible is the one who created everything in the universe, including the invisible bits. Take a look at what the Bible says here:

"I am the LORD; that is my name! I will not yield my glory to another or my praise to idols. (Isaiah 42:8)
For the LORD your God is a consuming fire, a jealous God. (Deuteronomy 4:24)
The LORD is exalted over all the nations, his glory above the heavens. (Psalm 113:4)
Yours, LORD, is the greatness and the power and the glory and the majesty and the splendor, for everything in heaven and earth is yours. Yours, LORD, is the kingdom; you are exalted as head over all. (1 Chronicles 29:11)
All the angels were standing around the throne...They fell down on their faces before the throne and worshiped God, (Revelation 7:11)

Most people today only have a surface-level understanding of God, they haven't truly connected with Him.

God owns everything, including us, and He just wants what's rightfully His. He commands us to love Him and show it by serving Him.
This may be hard to accept, but God has complete control over the world He created. If we invented something, we would have the authority to decide the regulations. But, according to God:

'Love the LORD your God with all your heart and with all your soul and with all your strength.
These commandments that I give you today are to be on your hearts.' (Deuteronomy 6:5-6)

God could've made life easier by making us robots without free will, but He didn't. But that's the opposite of God's plan. He wanted creatures that could willingly and freely love Him.
A being that was somewhat like God.

Free will can lead people to reject you, which is a potential downside.

When you give someone the ability to make their own choices, they might not listen to you, and that's what happened to us.
There's an issue because we all have flaws or make mistakes that the Bible calls sin. Going against God's nature and holiness through these things is like breaking the unchangeable laws of the universe that He put in place. These mistakes have caused us to be far away from God.

'The heart is deceitful above all things and beyond cure. Who can understand it?'(Jeremiah 17:9)
'But who can discern their own errors? Forgive my hidden faults.' (Psalm 19:12)

You are accountable for all the bad things you do, and you owe God a debt that must be paid.

The things we need to do for God:
'And forgive us our debts, as we forgive our debtors.' (Matthew 6:12)

God's perfect purity is being violated by all of these things. Do you see it?
Have you ever stolen something? The Bible says it's a bad thing to do.
The Bible teaches us that it's wrong to desire things that belong to other people. Have you ever felt envious of your friend's wife, life, stuff or house?
Honoring our parents is a requirement from God. Did you ever argue with your parents when they told you to do something?
It's against God's wishes to use His Name carelessly or without respect. Have you ever said God's Name as a swear word or without thinking?

From big to small, God knows it all. Keep in mind, we learned that we can't leave any bad thing unchecked. Eventually, ALL the bad things will be scrutinized. In other words, living in agreement with the unchanging laws of the universe. The Bible puts it as mitigating God's anger. It can be shocking to hear this if you believe that God loves all humans greatly. So much so, that people have come to believe that God could never be wrathful with anybody because of any wrong they do. It's common for people who lack basic knowledge to argue that God is supposed to love us no matter how we live.
Yes, God loves the world, but we can't ignore His holiness either. There's no way that can be done.

Trying to understand the eternal God through our expectations, behavior, and earthly norms proves impossible.
The Bible tells us about a God who is completely out of this world. We can't expect God to follow our rules, it's like hoping for something fake that won't last long.

People wrongly blame God for the things that go wrong in the world, but it is not God’s fault. His creation was flawless. Adam made a mistake and now we're all flawed.

As it is recorded in the Bible...

'For all have sinned (done wrongs things), and do need the glory of God. wrongs' (Romans 3:23)

So, being a good person and doing 'good' things cannot save you from the terrible penalty of the wrong thoughts, attitudes and conduct. It's only Jesus Christ who can do this. Going to church and being kind doesn't mean you'll go to heaven. The key to receiving God's forgiveness is acknowledging our wrongdoings and seeking repentance. And then we must live totally for God.
Again, the Bible teaches us that the result of our bad choices is facing eternal punishment in hell:

'For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.' (Romans 6:23)

God's Solution for Your Wrongs

The good news is that God has a way to make up for all the wrong things we do, so we can follow the laws of the universe that never change.
Jesus Christ was sent by God to die and rise again, as part of God's glorious plan. This incredible plan was executed for everyone to see, including humans, angels, and Satan. No other approach can make things right for our wrongs.

People always wonder why God is so strict if He is supposed to be a loving God. God's nature is intertwined with love., but, the Bible is very clear, you cannot have His love without His terrifying justice as well. They're both necessary.
It's impossible to fully comprehend the Eternal God with our own expectations. Believing God will obey our rules gives us an incorrect understanding of Him. You can't hide your thoughts from God because He knows everything.

Totally Yield Your Life to God Is Next

When you've genuinely expressed your apologies, it's common to feel called to live a life for God. Following this is God's command. It's like making God the leader of our lives for eternity. We aim to obey every principle in the Bible.
According to the Bible, that's the appropriate order of things:

'Then he said to them all: "Whoever wants to be my disciple must deny themselves and take up their cross daily and follow me.' (Luke 9:23)

God never said this, not once; ‘Just be a good or nice person, do many good things for other people, and you will be saved and live with me in heaven.’
Here's what the Most High God has to say about getting forgiveness for your sins:

'To some who were confident of their own righteousness and looked down on everyone else, Jesus told this parable:

"Two men went up to the temple to pray, one a Pharisee and the other a tax collector. The Pharisee stood by himself and prayed:'God, I thank you that I am not like other people--robbers, evildoers, adulterers--or even like this tax collector. I fast twice a week and give a tenth of all I get.'
"But the tax collector stood at a distance. He would not even look up to heaven, but beat his breast and said,'God, have mercy on me, a sinner.'
"I tell you that this man, rather than the other, went home justified before God. For all those who exalt themselves will be humbled, and those who humble themselves will be exalted." (Luke 18:9-14)

The religious man in the story did not commit "bad" sins like murder, but that did not mean God forgave him.
God forgave the tax collector because he had a genuine change of heart and repented. It is a humiliating thing to admit we are and have been, wrong and to surrender our lives utterly to God. Nonetheless, we need to admit our mistakes and give up control to God to be saved.

Jesus Christ expressed:

'He called a little child to him, and placed the child among them.
'And said, “Truly I say to you, unless you change and become like children, you will not enter the kingdom of heaven.' (Matthew 18:2-3)

Mere acts of kindness for God won't secure our salvation; salvation from hell doesn't come from being virtuous.

'You were saved by faith in God, who treats us much better than we deserve. This is God's gift to you, and not anything you have done on your own.' (Ephesians 2:8)

Do You Want To Confess Your Wrongdoing And Let Jesus Pay For It, Or Not?

'Then he said to them all: "Whoever wants to be my disciple must deny themselves and take up their cross daily and follow me.' (Luke 9:23)

Taking up your cross every day means living a life that pleases God, not yourself.

It is also written in the Bible that:

'Therefore, I urge you, brothers and sisters, in view of God's mercy, to offer your bodies as a living sacrifice, holy and pleasing to God--this is your true and proper worship. (Romans 12:1)

'But in your hearts revere Christ as Lord. Always be prepared to give an answer to everyone who asks you to give the reason for the hope that you have. But do this with gentleness and respect.' (1Peter 3:15)

All in all:

You acknowledge the severity of your sins in the eyes of God. You honestly admit your mistake before God. Jesus Christ becomes your teacher. It's a lifelong pledge. And as the Bible says, we live for God Learn more about God by reading the Bible every day. Building a daily habit of prayer to God. Teaching others about God's word. Being directed by God to serve others. Your life's mission becomes serving God Most High for the rest of your days.
We get to go to heaven with our Father in Heaven.

You can read a Bible here, start with the book of Mark: https:/bit.ly/3j1cmbe or https://www.sermoncentral.com/bible/new-living-translation-nlt/mark-1?passage=Mark+1