"Anyone who lives on milk, being still an infant, is not acquainted with the teaching about righteousness. But solid food is for the mature, who by constant use have trained themselves to distinguish good from evil" (Heb. 5:13-14 NIV).
I was once in a discussion with some brethren on an internet forum. We didn't seem to agree on the doctrine of Righteousness. I insisted that we have to pursue righteousness although the righteousness of the Lord has been imputed on us. Their position was that there is nothing we need to do about righteousness because it is already given—freely.
It is true that the righteousness of Christ has been imputed on us—freely. There is no debate about that. Nevertheless, that is just part of the whole—one side of the coin. There is a part that we have to play to make it complete. To me, righteousness is like a baby. A baby doesn't have to do anything to 'merit' its birth. But once born, it has to grow. Its growth involves factors and forces outside itself as well as those inside. It has to drink milk (to start with), and with time begin to eat tough stuff, it has to train to crawl, stand, walk and eventually run. This is the reason for which the Bible exhorts us to "pursue righteousness" (1 Tim. 6:11). It may sound paradoxical to ask people to pursue what they already have. But look at it this way: let me go back to the baby analogy. When a baby is born, it is not fully developed. It is his participation and co-operation in eating and exercising that will help it grow. For those of you who have kids, you will realise that sometimes they don't want to eat, or if they do, they would only want to eat ice-cream. Growth is not just increasing in weight and stature. And eating is not just a matter of filling the stomach with anything. Balanced diet is critical.
The child's efforts and co-operation in eating and training is what represents our 'pursuit of righteousness'. We are born without doing anything, but we grow out of our initiatives to feed accordingly.
The pursuit of righteousness involves training in the Scripture in order to be able to distinguish good from evil (Heb. 5:14). Remember that sometimes it takes constant training in the spiritual food (the Word of God) in order to be able to tell the difference between what pleases the Lord and what doesn't. This is because right and wrong are not always black and white (Eph. 5:10). This is also the reason the Bible exhorts:
"Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is—his good, pleasing and perfect will" (Rom. 12:2 NIV).