The world of yesterday as well as today struggled to come to comprehend salvation on God's terms. Unbelief splintered between those who felt they were too smart for a crucified Jesus and those who desperately sought for a sign, another sign, a miracle, a bigger miracle, evidence, even more evidence. They were seeking for proof whilst they rejected all proof, a sign when they refused all signs and evidence when they had closed their mind to the evidence that flowed freely from the hands of the creator.
The evidence for Divine activity is all around us and within us. His fingerprints are stamped on the intricacies of His creation, the bible is as robust a proof filled text as you will find, the saving work of Jesus on the Christ was a plan fulfilled to the tinniest detail from the Old Testament blueprint. The proof is there if you are willing to accept it.
Many stumbled at the cross of Jesus; that placed that condemned man and his efforts to reach God and displayed the love and earnestness of God in reaching man! It was because man had been wrong about Jesus that they had fashioned Him a bloody altar of wood. To accept God's salvation in the sacrifice of His Son, would be to admit we had been wrong about Jesus all along, and that was a bitter pill to swallow. Infinitely more bitter is the taste of eternal loss, if we continue to be wrong about Jesus. If He is whom He claimed to be; "the way, the truth and the life" then life's greatest tragedy is to be wrong about Jesus.