God made man in the image and likeness of God (Ge 1:26). He "breathed into his nostrils the breath of life; and man became a living being" (2:7). Hebrew for "breath" means breath, wind, or spirit. "God is spirit" (Jn 4:24) and he communicates with man. "That which is known about God is evident within them; for God made it evident to them" (Ro 1:19). "God has allotted to each a measure of faith" (12:3). "'The word is near you, in your mouth and in your heart'" (10:8). It is "with the heart a person believes" (:10). It applies to "the hidden person of the heart" (1Pe 3:4) or "inner man" (Ro 7:22).
You have to pay attention to God. "Since the creation of the world His invisible attributes, His eternal power and divine nature, have been clearly seen, being understood through what has been made, so that they are without excuse" (Ro 1:20). But "even though they knew God, they did not honor Him as God" (:21). It's because "a natural man does not accept the things of the Spirit of God" (1Co 2:14). It's an eternal decision. "'Fear Him who is able to destroy both soul and body in hell'" (Mt 10:28). Paul prayed that "may your spirit and soul and body be preserved complete" (1Th 5:23).
"Those who worship Him must worship in spirit and truth" (Jn 4:24). But spiritual things are foreign to the natural man "because they are spiritually appraised" (1Co 2:14). Therefore you must become a "new creature" (2Co 5:17). When that happens "old things passed away; behold, new things have come" (:17). You become a new person "inwardly; and circumcision is that which is of the heart, by the Spirit" (Ro 2:29). "'That which is born of the Spirit is spirit'" (Jn 3:6). Then "our inner man is being renewed day by day" (2Co 4:16).