Buy the truth, and sell it not… buy wine and milk without money and without price. – Proverbs 23:23; Isaiah 55:1

“Buy the truth.” Let us correct an error here. Some might suppose that Christ, and the gospel, and salvation-all of which are included in the truth-can be bought. They can, but they cannot. They can in the sense of the text; they cannot in any other sense. You cannot purchase salvation; merit cannot win it. Christ’s price is, “Without money and without price.” Has not the prophet so worded it? “Yea, come, buy wine and milk, without money and without price.” Salvation is of free grace, and is from the very necessity of its nature, gratis. You cannot merit it; you cannot earn it. It is not of the will of man, nor of blood, nor of birth, but “He will have mercy on whom He will have mercy, and He will have compassion on whom He will have compassion.”

To be saved, give up everything that must be given up, in order to your receiving the free salvation. Every sin must be given up. No man shall go to heaven while he lives in, and favours any one, sin. A man may sin and be saved, but he cannot love sin and be saved. Give up, then, thy drunkenness, if that be thy sin. Give up, then, thine unchaste living, if that be thy sin. Conquer that angry temper, that love of greed-whatever it is that keeps thee back from Christ. Buy the truth, and give up these. Thou wilt not merit salvation then; but if this must be given up, let it not stand in thy way. Give it up, man! Since thou canst not have thy sin and have Christ too, get a divorce from thy sin and take holiness, and take the Saviour. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/3449.cfm