Well spotted Juk.
Here it is spelt out by Paul. Prior to already having the life of God within him, nobody can possibly comprehend what Jesus did on the cross.
1Cor1v18For the preaching of the cross is to them that perish foolishness; but unto us who are saved it is the power of God.
From the creation of the earth, Jesus has worked by the Holy Spirit in the hearts of man calling them to God.
God still does that today, planting his seed, (sperma) in the heart of any willing recipient. It is that planting that first produces new life, long before anyone can possibly make sense of what the cross is about. Spiritually dead men cannot possibly comprehend the story of the cross!
That is why the Holy Spirit is always at work in men's hearts, and their response is entirely down to their own hardness/softness of heart.
John1v1
1In the beginning was the Word (Logos), and the Word was with God, and the Word was God. 2The same was in the beginning with God. 3All things were made by him; and without him was not any thing made that was made.
This clearly refers to God the creator, who is Jesus, a long time prior to his incarnation!
4In him was life; and the life was the light of men. 5And the light shineth in darkness; and the darkness comprehended it not.
Jesus is the light of the whole world!
6There was a man sent from God, whose name was John. 7The same came for a witness, to bear witness of the Light, that all men through him might believe. 8He was not that Light, but was sent to bear witness of that Light. 9That was the true Light, which lighteth every man that cometh into the world. 10He was in the world, and the world was made by him, and the world knew him not. 11He came unto his own, and his own received him not.
12But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:
This verse refers not merely to the physical Jesus we see walking in Gallilee, but to the logos, light of the world, the God who created all things. Receiving the creator God via the Holy Spirit brings new life to those living even in the darkest corners of the world.
From that point, taking hold of the cross can turn a life of bondage into a life of salvation power.
As a child born into a non christian home, I knew nothing of the gospel. One day whilst a child, the overwhelming love of God came so close to me in my bedroom, and I asked Him to never forget me. He kept his word.
Another time in my early teens some kids were arguing about who went to heaven and who went to hell. One of the older boys who was an altar boy at the local church boldly stated, "that's easy, good people go to heaven and bad people go to hell."
As he said that, it was as if a blanket of truth and understanding descended on me, and I clearly heard God speak that He lived in my heart not churches, and that although I was bad and everyone else was bad, God had made the way.
A decade or so later when I got accosted by evangelists, I refused to listen because, after what God had told me, I didn't want anything to do with churches. It took me some time before I realised they were talking about the one I already knew!
Only then did I become a Christian.