What did Christ tell the Jews of Old about who He is and how He gives eternal life? They do not believe in Him because they do not have the Word (Christ) abiding in them. They searched the Scriptures believing they had eternal life, the Scriptures (Word of God) testify of Christ. But they stumbled at the Word (Christ) because they were seeking eternal life through their own natural righteousness through obedience to the Law. Therefore Christ (the Word) became a stumbling stone and an offense to them preventing them from believing according to grace through faith.
Joh 5:37 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.
Joh 5:38 And ye have not his word abiding in you: for whom he hath sent, him ye believe not.
Joh 5:39 Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.
Joh 5:40 And ye will not come to me, that ye might have life.
Ro 10:3 For they being ignorant of God's righteousness, and going about to establish their own righteousness, have not submitted themselves unto the righteousness of God.
Ro 10:4 For Christ is the end of the law for righteousness to every one that believeth.
The corruptible seed is natural and comes by natural birth through Adam. The incorruptible seed is Christ, the Word of God who lives and abides forever.
My point being we cannot separate the written Word of God from Christ Jesus our Lord. Because salvation comes by hearing the Word (Christ' gospel). This is the hour/time/age Christ spoke of as having come when man may hear the voice of Christ and all who hear and believe have eternal life.
Joh 5:23 That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him.
Joh 5:24 Verily, verily, I say unto you, He that heareth my word (gospel of Christ), and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.
Joh 5:25 Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live. [Ye MUST be born again]
Joh 5:26 For as the Father hath life in himself; so hath he given to the Son to have life in himself;
Joh 5:27 And hath given him authority to execute judgment also, because he is the Son of man.