2Jo 1:2, For the truth's sake, which dwelleth in us, and shall be with us for ever.
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Jhn 14:6, Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me.
Col 1:27, To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:
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Col 3:16, Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord.
I agree. If someone, in their heart, is harboring sin, it will affect their theology for the worse.
There is a funny thing I realised about my phrase, truth exists but it exists outside ourselves.
In faith this is actually not true, as Jesus is the truth and He lives in us through His word and the Holy Spirit.
But in the sense can we know truth is truth, and the answer is only by faith.
Philosophers tried to prove God from first principles and from our own personal consciousness.
Unfortunately everything is based on experiential ideas and constructs, which rely on external information and facts.
Everything is filtered through our senses, and our brains take all the input and give us an interpretation of reality.
It means no matter how certain we are, it is all founded on limited physical interactions and assumptions.
Now one could say this is very cynical, but I would answer pragmatic optimism. We optimistically believe the facts are true, and therefor can draw reasonable conclusions on which to base our lives, understanding this is pragmatic optimism.
The reason I say this Nietche ended up saying God was dead, but what he actually could only mean is the absolute God that could be proved without assumption was dead. But what he neglected to continue to say is that this is true of everything we experience, ie. there is no absolute certainty but pragmatic optimism. He also left out the cynicism and purposelessness destroys the soul, as we are grounded in love and meaning from our family and social contacts. So we need pragmatic optimism, which works and is as meaningful as absolute truth, because through it we can find God who is the absolute truth.
God has created this world, so that the key to life is in seeing how grounded we are in love, and to choose this love and life to continue within. Jesus went so far as to say those people so grounded will listen to Him, because He is love and He is from the Father.
I blame scientific believers who thought they could prove God through science, and found out that science told a more complex story, and even their convictions needed to be based on love and faith, not factual certainty. The more we have discovered the more we know this universe could only exist if it had been created. Unfortunately unbelief has gripped scientists that God must not be the solution, there must be infinite multi verses, and creation must echo eternally. All this is pure religious speculation beyond science, but they would rather create a religion of science than explore the creator who made everything.
And equally believers often claim to follow the truth, but are too scared to explore this in the wider world. There are answers, but certainly not as the world dictates or projects. The law of God is stunning, written 3,400 years ago still speaks to us today. God bless you