Justice and Mercy, Not Fasting

Zechariah Chapter 7:3-10
"The people asked the Lord: Should I mourn and fast in the fifth month, as I have done fore so many years?.....the Lord replied: When you fasted and mourned in the fifth and seventh months for the past seven years, was it really for me that you fasted?.....Administer true justice; show mercy and compassion to one another."
I easily notice other Christians' problem and give judgement. Most of the time , it happens when the Christians are brothers or they do not belongs to my B/T. It does not help the whole situation. The dangerous part is that I will fall into sin because of this. What sin? It may be -- judgement, blame shift - their behaviour or attitude affect the church, the B/T....
But where are my mercy , love towards them . Did I try my best to talk to them in love or pray for them earnestly?
God has given me a mission" Seek and save the lost". The above problem is also one of my mission too.
Ezekiel 3:17
"Son of man, I have made you a watchman for the house of Israel; so hear the word I speak and give them warning from me. When I say to a wicked man, ' You will surely die,' and you do not warn him or speak out to dissuade him from his evil ways in order to save his life, that wicked man will die for his sin, and I will hold you accountable for his blood. But if you warn the wicked man and he does not turn from his wickedness or from his evil ways, he will die for his ; but you will have saved yourself.....Since you did not warn him, he will die for his sin. The righeous things he did will not be remembered, and I will hold you accountable for his blood. But if you do warn the righteous man not to sin and he does not sin, he will surely live because he took warning, and you will have saved yourself."
I have deep conviction of the above scriptures . However, I will hesitate if I need to confront brother. God uses today's QT to remind me to treat every Christians the same , there should not be any favouritism or partiality.