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.
We have received, not the spirit of the world - the "spirit that now worketh in the children of disobedience" (Ephesians 2:2). This spirit is natural in the unregenerate, and needs not to be received (Ezekiel 13:3; 1 John 4:4).
Spirit which is of х ek (G1537)] God - i:e., which comes FROM God. We have received it only by the gift of God, whose Spirit it is (1 Corinthians 2:11).
That we might know - experimentally.
Things that are freely given to us of God - God's gift of salvation in Christ, now preached without admixture of worldly wisdom (1 Corinthians 2:4), and the "things which God hath prepared for them that love Him" (1 Corinthians 2:9).