Receiving the grace of God in vain brings to mind a parable of Jesus from Luke 8. In verse 13 Jesus explains the meaning of the Parable of the Sower as regards the Gospel falling on rocky soil.

These are people who hear the Gospel, think it sounds great, and essentially try it out. They believe with their mind, but not with their heart. They mentally affirm the facts or the doctrine, but their trust is never placed in Christ.