Belonging to Christ gives us hope; not a pie-in-the-sky wishful hope, but a confident assurance that Jesus’ life and death assures us of ultimate healing; if not here – and contrary to what some say, it is manifestly not God’s will that everyone be illness-free here –we are promised that in heaven there will be no sickness or pain (Revelation 21). Suffering such things also helps to direct our attention to that time and place and causes our hearts to long for them.
Enduring such illness also teaches us patience and reliance upon God here, and it serves as an opportunity to others to render service to us, and to pray for us.
Regarding wellness, we are stewards of our bodies, and we are to care for them in a responsible and biblical way.