And this is the record, that God hath given to us eternal life, and this life is in His Son. He that hath the Son hath life… – 1 John 5:11,12

Whoever in this world possesses Christ by faith is most certainly alive unto God by a life eternal. I shall remark that having the Son is good evidence of eternal life, from the fact that faith by which a man receives Christ is in itself a living act. Faith is the hand of the soul, but a dead man cannot stretch out his icy limbs to take of that which is presented to him. If I, as a guilty, needy sinner, with my empty hand receive the fullness of Christ, I have performed a living act; the hand may quiver with weakness, but life is there. Faith is the eye of the soul, by which the sin-bitten sinner looks to Christ, lifted up as Moses lifted up the serpent in the wilderness; but from forth the stony eyes of death no glance of faith can dart. There may be all the organization by which it should look, but if life be absent the eye cannot see. If, therefore, my eye of faith has looked alone to Jesus, and I depend upon Him, I must be a living soul, that act has proved me to be alive unto God. Looking to Jesus is a very simple act, indeed, it is a childlike act, but still, it is a living one: no sight gleams from the eyeballs of death. Faith, again, is the mouth of the soul; by faith we feed upon Christ. Jesus Christ is digested and inwardly assimilated, so that our soul lives upon Him; but a dead man cannot eat. Whoever heard of carcasses gathering to a banquet? There may be the mouth, the teeth, and the palate, and so forth, the organization may be perfect, but the dead man neither tastes the sweet nor relishes the delicious. If then, I have received Christ Jesus as the bread, which came down from heaven, as the spiritual drink from the rock, I have performed an action which is in itself clear evidence that I belong to the living in Zion. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0755.cfm