1 Corinthians 2:14 The unbeliever does not receive the things of the Spirit of God, for they are foolishness to him. And he cannot understand them, because they are spiritually discerned. 2:15 The one who is spiritual discerns all things, yet he himself is understood by no one. 2:16 For who has known the mind of the Lord, so as to advise him? But we have the mind of Christ. [NET]
Do not be concerned about those who do not understand or receive grace. It is foolishness to them. They have the mind of the world. Grace is understood through His Spirit, and you have His Spirit. By His Spirit, you have His Mind. Rest in this.