We must compare spiritual things with spiritual things and not measure spiritual things by natural standards. Paul makes a distinction between the spiritual and natural. Faith is a spiritual entity since its origin is Divine. A calling in life and ministry that is Divinely inspired is a spiritual thing, and the productivity and effectiveness cannot always be measured by standards such as money, visibility or popularity. A visit to the physician reveals standards of health such as blood pressure, cholesterol and weight. Perhaps the standards of a healthy calling may be Divine favor, guidance, deliverance and provision. To measure a Divinely inspired occupation or calling by money, popularity or visibility may not always be appropriate.