For as the Father raiseth up the dead, and quickeneth them; even so the Son quickeneth whom He will. – John 5:21

This living union is Christ’s life in us. It is given to Him, not only to take us in our feebleness; but it is His divine prerogative to impart life to us, and to call dead men, and to make them live. “For as the Father raiseth up the dead, and quickeneth them; even so the Son quickeneth whom He will.” This is how we come to have life in connection with Him. His life flows into us, as out of the tree into the branches: so that we can truly say, with the apostle, “I live, yet not I, but Christ liveth in me: and the life which I now live in the flesh, I live by the faith to the Son of God, who loved me, and gave Himself for me.” The living union begins with our Lord’s life, and then that life flows into us, and we begin to live also.

O souls, if the life of Christ is not in you, you are dead while you live, and you will die forever when you die! Unless you get linked to Christ, you will be driven from the presence of God, and away from all that makes for true life and joy. Lay hold on Christ, and you will “lay hold on eternal life”; for He is “that eternal life which was with the Father, and was manifested unto us,” and living contact with Him is our only hope either for the present or for the future.

God grant to you and to me to have such a living union to Christ!~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2245.cfm