It’s not necessarily a sin to be under 20 years of age any more than it is a sin to be a pastor who is under 40.
Having said that, there are unique temptations for those who are young. One of these unique temptations is to presume one has the wisdom which can only be attained over the course of life.
In our church, we are doing a series on Christian decision making. It’s an extended exposition of Romans 12:1-2. The ongoing metaphor is to picture Christian decision making as a saw that must be sharpened. Wisdom is the saw Christians used to cut their way through life.
If you have no wisdom, then your saw is dull. Even if you have the best of intentions, and work as hard as you can, if you have no Christian wisdom, then making Christian decisions is like trying to cut down an oak tree with a butter knife.
While not all people develop sharp saws at the same rate, it is a biblical principle that only as we get older do we really develop wisdom (Proverbs 16:31, 20:29). Young people may be physically strong, but those with gray hair are wise.
If you are reading this and you are a teenager, don’t despair that you are working with a dull saw. That’s part of being young. But, be sure you lean on your parents and/or others who have sharpened their blades over the years.
If you are a young pastor (say under 40), don’t let anyone look down on you because you are young. Set an example for the believers. But, remember there is a lot of sharpening of your blade that needs to take place. Listen to advice and accept instruction. Eventually you’ll be wise (Proverbs 19:20). Seek wisdom. Keep looking for it. Pursue it like it is treasure (Prov 1-2).