The word “invigorated” literally translated means “to put life or energy into.” That which makes the difference between being spiritually dead and spiritually alive is God’s word. We know this from Jesus’ teachings.
After Jesus had been working som great miracles, we find that many followed him because of the miracles (John 6.2). Later, Jesus confronted them because it was apparent that they were only there for physical food (vv. 24-33). He challenged them to seek the spiritual food he offered, but many would turn away later when this spiritual food could not be swallowed (vv. 41-66). In their rejection of this spiritual food, they forfeited eternal life.
After these had turned away, Jesus said to those remaining, “It is the spirit that giveth life; the flesh profiteth nothing. The words that I have spoken unto you are spirit, and are life” (v. 63). The source of spiritual invigoration — life and energy — came from the Spirit and the words of Jesus Christ! When Jesus then asked his closest disciples if they, too, would turn away (v. 67), Peter replied, “Lord, to whom shall we go? Thou hast the words of eternal life” (v. 68). The twelve understood that Jesus’ words were the source of their spiritual life.
Those words spoken by Jesus, as well as the words taught by the Holy Spirit (cf. 1 Corinthians 12.13; Ephesians 3.3-6), are the only source of spiritual life. Cornelius feared God and prayed always. God answered his prayer with a vision, telling him to send for Simon, who would speak “words, whereby thou shalt be saved, thou and all thy house” (Acts 11.14). Those words were by inspiration of the Holy Spirit. Cornelius, although devout (Acts 10.2), was still spiritually dead in his sins until he exercised his faith in those words. His obedience of faith resulted in spiritual life from spiritual death for him and his household. That is what spiritual invigoration is: Life from death.
We must all recognize that, outside of Christ, we are spiritually dead (cf. Ephesians 2.1). Our spiritual life comes from Christ through his teachings. The gospel message declares God’s righteousness, which is God’s power to save (Romans 1.16-17). God has revealed the process of justification in the gospel. Man was not responsible for it, nor did it originate with man, for man could not have provided it. It was God’s plan for making man righteous. Paul refers to it as the “law of faith” (Romans 3.27). Paul also called it the “law of the spirit of life in Christ Jesus” (Romans 8.2). James referred to it as the “law of liberty” (James 1.25; 2.12). It is simply referring to the provisions God has put in place whereby man may be reconciled to him.
But what about after our spiritual birth? Despite the fact that some teach a “once saved, always saved” plan of salvation, that is not God’s “law of faith.” Faith must be nurtured, else it will die. Just as we need to continually eat physical food to remain alive physically, we must also continually feed on spiritual food to remain alive spiritually.
Peter’s admonition to newborn disciples was that they “desire the spiritual milk which is without guile, that ye may grow thereby unto salvation” (1 Peter 2.2, ASV). This emphasizes the need for proper diet. We recognize this in the physical realm. Proper diet and proper exercise are essentials to physical wellness. Both must continue. No one can eat just once and expect that to last 60 or 70 years. Why would anyone think he can grow spiritually without spiritual nourishment? The same physical problems which would arise from physical malnutrition will also arise spiritually from spiritual malnutrition.
To be spiritually strong, we must continually feed on God’s word and then continually exercise our faith in obedience to those words (cf. Romans 1.5; 16.26). When we continue to ignore our spiritual hunger, we become weak. As our spiritual strength weakens, our resistance to fleshly lusts is unable to resist the urge to satisfy those lusts. It is inevitable that we will sin. “Each man is tempted, when he is drawn away by his own lust, and enticed. Then the lust, when it hath conceived, beareth sin: and the sin, when it is full grown, bringeth forth death” (James 1.14-15).
We must exercise ourselves for the purpose of becoming godly, not ungodly (1 Timothy 4.7-8). Spiritual malnutrition is an inevitable result from any doctrine that does not agree with the words of Jesus (1 Timothy 6.3-6). The reason given by Paul was that one’s godliness will become discontented from feeding on a diet of unsound doctrine. Those who are not content with living godly lives view the keeping of God’s words as a weariness (Isaiah 43.22; Micah 6.3; Malachi 1.13; 3.14). Remember, only Jesus’ words can provide you with life abundantly (John 10.10).