As for 1 Corinthians 2:14, the distinction should not be viewed as saint verses sinner. Rather, the contrast should be drawn between the wisdom of God and the wisdom of man. The "spiritual" person can discern the things of God through the indwelling of the Holy Spirit, whereas the "natural" man cannot understand the things of God because he tries to do so by means of his mere intellect (discernment is to be rooted in Scripture along with the Holy Spirit aiding our understanding). This text is speaking of divine inspiration (1 Corinthians 2:13). It is speaking of God revealing the truths of the gospel, which has already been done through the apostles (Ephesians 3:3-5). Divine revelation is powerful enough to convert the lost soul to Christ (John 20:31; 2 Timothy 3:15). Carnal people cannot understand the things of God because they simply do not want to. They naturally refuse. The Apostle Paul's point in 1 Corinthians 2:14 is that a person who uses human wisdom to interpret spiritual truths will only come to view the cross as foolish and consequently die spiritually. In short, this text has nothing to do with Calvinism.