The apostle John had to confront the false teaching regarding the nature of Christ. He begins in a similar way he begins his gospel that Jesus was fully human and God (1 J n. 1.1-3; 4.2; 5.6; 2 J n. 7).
However, a short statement in the third epistle gives us some information about our topic. Many proponents of the view that God promises good health use the verse to prove their view.  Here’s the verse: “Dear friend, I pray that you may enjoy good health and that all may go well with you, even as your soul is getting along well” (3 Jn. 2). This interpretation fails to take into account that this is a normal element in writing a Hellenistic letter. It is a health wish found throughout secular letters of that time. John recognizes the two dimensions – the spiritual and physical and was already convinced that Gaius’soul was on the right path. Verse 3 reads, “For I rejoiced greatly when the brethren came and testified of the truth that is in thee, even as thou walkest in the truth”(KJV).  John, then, adds that he is praying for two other things, namely, that Gaius would go well in everything and have good health. The first of these requests probably concerns the everyday affairs of Gaius’personal life.
The second request is for his physical health. This does not necessarily mean that John is requesting he be healed as we are not told he was sick.  However,  the meaning seems to point in the direction of “continuing in” (rather than of”being restored to”) good or decent health. In this verse, John uses one of the normal Greek verbs for a request or a wish directed to a deity. He does not use a verb of thanksgiving as if to say: “I thank the Lord, Gaius, that, because you are a believer, you are in good health.” Rather, the apostle asks for that favor to be granted by God. Such a request does not mean that God will automatically grant it.  While the Health Wealth Gospel people  of the Health and Wealth Gospel people think that good health is a Christian’s (new) birthright, John’s letter to Gaius points to the fact that one is continually dependent on God for health.” God’s higher purposes may be better served by a believer’s going through physical suffering and sickness-for the purification of his or her own soul. Such was the case for the apostle Paul (2 Cor. 12.7-10) and for all Christians after him who had profited from his insights as a result of his “thorn in the flesh”.