However the bible clearly teaches that we can know absolute truth and not of ourselves but by the Spirit of God. This is because God exists in a realm outside of our time space continuum. Not only does he have the fullness of all knowledge but he knows every future event because he exists outside of time and has seen everything come to pass already in our time based existence.
This is why Jesus could say some very *concrete* statements that spoke to this absolute truth. If you look at his teachings, he wasn't one to equivocate and often preceded his statements with "truly, truly I say you to".
If we have the Spirit of God we can know his thoughts which point to absolute truth:
1 Corinthians 2:11Jesus said we'd all know the truth and it would set us free:
For who knows a person's thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God.
John 8:32How do we know the truth? Again by the Spirit of God, and Jesus affirms this again:
you will know the truth, and the truth will set you free.
John 16:13Jesus makes it clear we can know the absolute truth, which postmodernism vehemently contends is impossible. While we will know the truth, we'll never come to full knowledge of the truth until we become glorified, but we are expected to gain more and more knowledge with each day (see 2 Peter 1) which is part of confirming our calling and election- because the more of God's Spirit you enter into, the more truth will permeate you because he's the Spirit of truth.
When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come.
1 Timothy 2:4This is also why we can stand on the authority of God's word and trust in his promises. The bible was written by the Holy Spirit who the Spirit of truth (John 14:26, 2 Tim 3:16-17).
who desires all people to be saved and to come to the knowledge of the truth.
And God proves this by littering the bible with 2500 prophecies, 2000 of which have come to pass and 500 which are in the process of being fulfilled. He's already seen everything come to pass so he can declare future events with no problem and that's why we can be assured that he has already won the victory as the book of Revelation describes and Satan is thrown into the lake of fire. Even when the world around us is burning and telling us we're crazy this gives us reason to hope for the Christ that is in us, which is the hope of glory.
John 16:33More about fulfilled prophecy to those interested:
I have said these things to you, that in me you may have peace. In the world you will have tribulation. But take heart; I have overcome the world.