Rooted and built up in Him, and stablished in the faith, as ye have been taught, abounding therein with thanksgiving. – Colossians 2:7

In olden times, the fury of persecutors has failed to make the servants of Christ deny the faith. The saints were taken to the stake, but the fires which devoured their bodies only burned their testimonies into the hearts of other witnesses. They were faithful even unto death. This glorious firmness in the faith is greatly needed now to resist the insidiousness of error. Besides, dear friends, it may, in the providence of God, happen that some of you will be taken away from the ministry which now feeds you, and what will you do if the word of God be not in your inmost souls? I have observed many who did run well when under a gospel ministry, who, when they have been removed into a barren region, have lagged and loitered in the race. Some whose principles were never very deep have given them up when placed in society which despised them. I pray you get such a hold of the gospel, that you need not be dependent upon the preacher or upon earnest companions. Let not your faith stand in the wisdom of man, but in the power of God. No truth will be of any use to you unless it is branded into you; yea and made to penetrate the marrow of your being. If you could give up truth you have never received it. He only has the truth of God who so holds it that he could never part with it…May you all be rooted and built up in Christ Jesus and established in the faith as ye have been taught, abounding therein with thanksgiving. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0980.cfm