Why is it not your place to judge another person?
It is not your place to judge another person because you are not his master or employer; the one who died for the believer is the judge. God has received that believer, and He alone will evaluate and deal with His own servant. Paul rejects judging others, since you are not the boss and do not pay their wages.
Les explains that Paul addresses this in the context of believers disagreeing over matters like eating meat. Some were saying that those who eat meat are evil. Paul responds, 'let not him who eateth not, judge him who eateth.' Les connects this to Romans 8, where no one can judge us because the one who died for me is the judge. When you encounter other believers whose lifestyle you think is wrong, you are in no position to judge. You may be able to point them to Scripture, but you cannot judge another person. Paul rejects judging out of hand. God has received him, and God is the one who will do it. Paul uses the example of a servant: you don't judge another man's servant because you're not his boss, not paying his wages. Don't judge someone else; you're not the boss, God is.
Who art thou that judgest another man’s servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand.