In Scripture the natural person (unregenerate, non-believer) who consistently responds to the carnal human impulses and desires of the flesh is contrasted to the spiritual person (godly believer) – yet as Christians we have a continual choice as to which nature we will allow to dominate (Mt 12:35; Rom 6:16; Gal 5:16-23; Eph 2:3-7; 1 Jn 2:16; 2 Pet 2:19). Even though we live in a natural body we should consistently be putting off the old sinful nature which is being corrupted by its deceitful desires, being made new in our mind’s attitude, and with His enabling putting on the new self, created to be like God (Gal 2:20; Eph 4:22-24). "If anyone is in Christ, they are a new creation. The old has gone, the new has come" (2 Cor 5:17). It is our responsibility to outwork this new 'naturally' spiritual lifestyle.
The natural mind cannot understand spiritual truths (1 Cor 2:14). “Those controlled by the sinful nature cannot please God”. As believers we are being transformed as we choose to crucify the old carnal nature and increasingly walk in the new way of life (Rom 6:4, 8:8, 12:1,2; Gal 5:24). Water baptism is an outer sign that a person has chosen to die to the old natural life and live a new life in Christ with a divine progression from the natural to the spiritual (Rom 6:5-13; 1 Cor 15:46; Col 3:9,10).
Our Christian life should be without any artificiality of putting on a show to impress, for any façade is ultimately uncovered. It takes supernatural means to make natural people truly spiritual.