All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad  is His slave and Messenger.
  is His slave and Messenger.
The Prophet  ordered us to show kindness and gentleness in many Ahadeeth; some are as follows:
  ordered us to show kindness and gentleness in many Ahadeeth; some are as follows:
1. Aa’ishah  narrated that the Prophet
  narrated that the Prophet  said: “Whenever gentleness is found in something it beautifies it, and whenever it is withdrawn from something it leaves it defective.” [Muslim]
  said: “Whenever gentleness is found in something it beautifies it, and whenever it is withdrawn from something it leaves it defective.” [Muslim]
2. Aa’ishah  narrated that the Prophet
  narrated that the Prophet  said: “Allah is Kind and likes kindness in all things.” [Al-Bukhari and Muslim]
  said: “Allah is Kind and likes kindness in all things.” [Al-Bukhari and Muslim]
3. Aa’ishah  narrated that the Prophet
  narrated that the Prophet  said: “Allah is Kind and likes kindness, and bestows upon kindness that which He does not bestow upon harshness, nor on anything else other than kindness and tenderness.” [Muslim]
  said: “Allah is Kind and likes kindness, and bestows upon kindness that which He does not bestow upon harshness, nor on anything else other than kindness and tenderness.” [Muslim]
4. Jabir ibn ‘Abdullah  narrated that the Prophet
  narrated that the Prophet  said: “One who is devoid of kindness is devoid of the goodness of everything.” [Muslim]
  said: “One who is devoid of kindness is devoid of the goodness of everything.” [Muslim]
Imam An-Nawawi  said: “All the above Ahadeeth establish the virtues of kindness, urge on adopting it as one's manners, and at the same time, they warn against harshness and cruelness.” [End of quote]
  said: “All the above Ahadeeth establish the virtues of kindness, urge on adopting it as one's manners, and at the same time, they warn against harshness and cruelness.” [End of quote]
Allah praised the Prophet  for his good conduct; Allah Says (what means):
  for his good conduct; Allah Says (what means):
• {And indeed, you are of a great moral character.} [Quran 68:4]
• {So by mercy from Allah, [O Muhammad], you were lenient with them. And if you had been rude [in speech] and harsh in heart, they would have disbanded from about you.} [Quran 3:159]
Therefore, you should know, dear Brother, that you should be kind to your brother. You are obliged to deal with him in good manners. Show him love, gentleness, and affection instead of harshness and cruelty; repent for your faults.
Know that this behavior may lead to hatred between you and your brother and to many other bad consequences. The Prophet  said: “If you show mercy to those who are on the earth, He Who is in the heaven will show mercy to you.” [Ahmad, Abu Daawood, and At-Tirmithi who graded it as Hasan]
  said: “If you show mercy to those who are on the earth, He Who is in the heaven will show mercy to you.” [Ahmad, Abu Daawood, and At-Tirmithi who graded it as Hasan]
Finally, we draw your attention to the fact that if your brother commits something forbidden in the Sharee’ah, you may deter him and rebuke him. This is only to prevent him from doing what is forbidden, not to take vengeance on him.
Know that when he refrains from what is forbidden, you should immediately stop being offensive towards him.
Allah knows best.