Read Romans 14:13 

Each one of us belongs to the same Lord. When we stop dictating, it is easier for others to mature as they follow the Lord's directing.

Freeing others means we never assume a position we're not qualified to fill. This, in one sentence, is enough to stop any person from judging another. We're not qualified. We lack full knowledge. 

How often we have jumped to wrong conclusions, made judgmental statements, only to find out later how off base we were...then wished we could cut off our tongue.

What keeps us from being qualified to judge?

We do not know all the facts.
We are unable to read motives.
We find it impossible to be totally objective.
We lack "the big picture."
We live with blind spots.
We are prejudiced and have blurred perspective.

Most of all, we ourselves are imperfect and inconsistent.

Excerpted from Charles R. Swindoll, Wisdom for the Way (Nashville: J. Countryman, a division of Thomas Nelson, Inc., 2001). Copyright © 2001 by Charles R. Swindoll, Inc. All rights reserved. Used by permission.