It takes years for a person to be trained properly in most cases; this statement could be applied to so much. It applies to those who judge others, “judge righteously”, as commanded by Jesus. It applies to all that profess to be Christian.
Example: I worked on military aircraft for 40 years. When I first started I was not allowed to work alone on those aircraft until I went through a rigorous “on-the-job training” (OJT) program that lasted a few years and involved lots of book study on my part. Also, I was constantly in the company of someone else that was further along in training when I was working on the aircraft; an overseer of sorts. My training involved testing my knowledge on occasion to see if I was moving in the right direction and retaining what I had been taught. This is such a good example in my opinion.
I believe the same could be said about Christians. Those that may be further along in their training (Mature Christians) should assist those that are not as far along. Much book study is necessary for all, especially for the brand new Christian. They need to learn at least a little bit about what they profess to believe in. Wouldn't you agree? They need a human overseer (a trainer of sorts) on occasion to keep them moving in the right direction. To test them occasionally might be a good idea as well. Those tests can come in more than one form. Book knowledge is absolutely great, but hands on experience and demonstrating knowledge is just as good or maybe better. By the way, a mature Christian doesn't have to have a title in front of their name. It is not necessary to be a seminary graduate, either.
So many think they are ready to judge others from a biblical standpoint. Most don't understand the word judge. Are they truly ready to venture off in this area? In my estimation, many are not ready due to biblical illiteracy. How can they remedy biblical illiteracy? Study the book for a very long time, cover to cover. Learn Christ's doctrines only; forsake the traditions and commandments of men. Seek a mature Christian to help you over the rough spots; an on-the-job trainer of sorts.
Let me ask you a question: Could the immature Christian tell right from wrong according to God's word? Could they share truths from God's word if they never study it? Might be something to think about.
Jesus did tell us to judge righteously. (I believe to judge means to separate/discern right from wrong correctly, then act accordingly to Christ's doctrines). I feel that the judging of others comes with qualifications attached to it also. We can't help others learn right from wrong until we ourselves have been helped and trained properly in that area. In my opinion, a person that judges another without being properly trained and very familiar with God's word is best described as a novice or an immature Christian. Get some training first through complete study of His word. See 2 Timothy 2:15 KJV.
No one is any better than anyone else, we are all in the same boat when it comes to sin (Romans 3:23 KJV).