Jesus said 'I am the way and the truth and the life. No-one comes to the Father except through me' (John 14:6). He makes it quite clear that no-one can approach God without first going through Him.
Why is it we have to go through Jesus? Can we not just speak to God? Many people claim to know God without acknowledging Jesus. How can this be? Why is Jesus Christ the only way to God?
Our sin comes between us and God
All have turned aside, they have together become corrupt; there is no-one who does good, not even one (Psalm 14:3).
God is perfectly holy and righteous, and in comparison, we are sinful and corrupt. Because of our sin, God won't come near us or allow us to come near Him.
In Isaiah 6:5, Isaiah saw God and described what happened to him. 'Woe to me!' I cried. 'I am ruined! For I am a man of unclean lips, and I live among a people of unclean lips, and my eyes have seen the King, the LORD Almighty.' Isaiah was immediately convicted because he knew he had sinned. His sin had to be dealt with otherwise he would have died.
Only Jesus can take our sin away
It is impossible for God to forgive us without a penalty being paid for our sins. We cannot pay that penalty ourselves, but God has provided a way for us to be forgiven. For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life (John 3:16).
Because Jesus is the Son of God, He is of infinite value and His sacrificial death is sufficient to atone for all of our sins. His death therefore, is the only penalty God accepts. Salvation is found in no-one else, for there is no other name under heaven given to men by which we must be saved (Acts 4:12). In addition He has been resurrected from the dead and now sits at the right hand of God. Therefore he is able to save completely those who come to God through him, because he always lives to intercede for them (Hebrews 7:25).
Many people know of God but not all have a relationship with Him
We can learn a lot about God through reading the Bible or listening to others talking about Him or even looking at the world He created. However we can do this without making our peace with God. We can recognise our guilt and confess our sins to God, but if we do not believe in Jesus Christ then our sins will remain unforgiven and we will still be in bondage to them. Jesus said '...if you do not believe that I am the one I claim to be, you will indeed die in your sins' (John 8:24).
You can support a football team for years with much loyalty and yet probably none of the players will ever know you personally. Likewise, there are many religious people who are loyal and fervent for God and yet do not have a relationship with Him. Some of these people will call on the name of Jesus Christ and some will even work against God.
In John 10:27 Jesus said My sheep listen to my voice; I know them and they follow me.