Here is the value or prinicple:
Healthy Biblical discipleship should flow two ways...being discipled and discipleshing another. Someone more spiritually mature should be discipling, shaping and pouring into you. And you need to be discipling, shaping and pouring into someone not yet as far along in the faith as you are. We need both in our lives to bring humilty and fruitfulness. I am experiencing this right now in my life and it is proving to be tranformational.
The Biblical basis is simple. Let's call it the "Rule of 2" = 2-way discipleship as seen in 2 Timothy 2:2 which says:
You have heard me teach things that have been confrimed by many reliable witnesses. Now teach these truths to other trustworthy people who will be able to pass them on to others. 2 Timothy 2:2
If you are not currently experiencing this type of 2-way discipleship, I encourage you to ask the Lord for it. Pray and believe that he will set this up in your life. He may even ask you to help him.