I agree the bible says that. For myself, that is not proof, it is, as stated, faith.
First, one must understand that All Mankind Died when Adam and Eve ate the forbidden fruit "In the Day you eat of it you will SURELY DIE". Romans 5:12 clearly shows that Adams act brought Sin and death upon the WHOLE Human Race.
One must ask the Question. What kind of "death" was it (since they did not die immediately)? The Answer is that it was a spiritual death.
The next question is "What was the Extent of this Spiritual Death"? The answer again is explained by the Apostle Paul in Romans (quoting the Old Testament)- "There is NONE who Seeks for God" "There is none who does GOOD".
Thus Mankind stopped Seeking God after Adam's disobedience. None does Good (which is affirmed by our Lord's words to the Rich Young Ruler "There is NONE GOOD but God")
Then the next LOGICAL conclusion is "How does anyone Seek God, if Mankind is dead in Trespasses and Sin"? The answer is Regeneration (a New Heart) and a New Mind (one that Loves God than one that runs away and hates Him).
If you Believe and have Faith - It is a Miracle of God - BECAUSE MANKIND BY DEFAULT IS DEAD.