When we receive the Spirit of God, we can know the things given to us by God  -  1 Corinthians 2:12

Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God.

When we have the Holy Spirit, He is able to share with us the deep truths of God. Apart from the Spirit, who is from God, we could never know the things that God freely gives to us.