John 5:37-40 And the Father himself, which hath sent me, hath borne witness of me. Ye have neither heard his voice at any time, nor seen his shape.  And ye have not his word abiding in you: for whom he hath sent, him ye believe not.  Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me. And ye will not come to me, that ye might have life.

It's a progressive walk day by day. If we remain the same day after day, we are stagnated. It's not by human effort or study or any other human effort. Even when we study the Scripture, we have to be careful that we are in the Spirit or else it will bind us up rather than creating life in us. The Jews thought that, in the Scriptures, they had eternal life. However, life is in knowing the Father.

Many today think that they have eternal life in the Scripture.  They study and argue, but never hear His voice or at any time see His shape.  They have not His word abiding in them.  They don't believe that there is an experience other than their theoretical theology.  And they think that their rationalized pseudo-faith will save them.