I am the resurrection, and the life: he that believeth in Me, though he were dead, yet shall he live. – John 11:25

Because I live, ye shall live also. – John 14:19

From causes variable the effects are variable; but remaining causes produce permanent effects. Now Jesus always lives. Yesterday, dear brother you were exalted in fellowship with Him, and stood upon the mountain top; then your heart was glad, and your spirit rejoiced, and you could say, “I live in Christ.” To-day darkness has intervened, you do not feel the motions of the inner life as you did yesterday, but do not therefore conclude that the life is not there. What is to be your sign; what is to be the rainbow of the covenant to you? Why, that Jesus lives. Do you doubt that He lives? You dare not. You trust Him, doubt not then that you live, for your life is as sure as His. Believe also that you shall live, for that also is as sure as the fact that He lives. God gave to Noah, a token that He would not destroy the earth-it was the rainbow: but then the rainbow is not often seen; there are peculiar circumstances before the bow is placed in the cloud. You, brother, you have a token of God’s covenant given you in the text which can always be seen, neither sun nor shower are needful to its appearance. The living Christ is the token that you live too. God gave to David the token of the sun and the moon; He said if the ordinances of day and night should be changed, then would He cast off the seed of David. But there are times when neither sun nor moon appear, but your token is plain when these are hidden. Christ at all times lives. When you are lowest, when you cannot pray, when you can hardly groan, when you do not seem to have spiritual life enough even to heave a desire, still if you cling to Jesus this life is as surely in you as there is life in Christ Himself at the right hand of the Father. What? Is there such a bond between me and Christ? Is there such a link between His life and mine? Blessed be His name! Adored be His infinite condescension! ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0968.cfm