As it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love Him. But God hath revealed them unto us by His Spirit; for the Spirit searcheth all things, yea, the deep things of God.-1 Corinthians 2:9-10

How very frequently at our prayer meetings do we hear our brethren describing heaven as a place of which we cannot conceive! They say, “Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love Him;” and there they stop, not seeing that the very marrow of the whole passage lies in this: “But God hath revealed them unto us by His Spirit.”

Any one who reads the connection will discover that the apostle is not talking about heaven at all. He is only speaking of this: that the wisdom of this world is not able to discover the things of God; that the merely carnal mind is not able to know the deep spiritual things of our most holy religion. He says, “We speak the wisdom of God in a mystery, even the hidden wisdom, which God ordained before the world unto our glory, which none of the princes of this world knew: for had they known it, they would not have crucified the Lord of glory. But as it is written, Eye hath not seen, nor ear heard, neither have entered into the heart of man, the things which God hath prepared for them that love Him. But God hath revealed them unto us by His Spirit; for the Spirit searcheth all things, yea, the deep things of God.”…”But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.” I take it, that this text is a great general fact, capable of specific application to certain cases; and that the great fact is this: that the things of God cannot be perceived by eye, and ear, and heart, but must be revealed by the Spirit of God; as they are unto all true believers. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0056.cfm