Compassion, mercy, leniency: That is what we ask from God, is it not? What do we want in Heaven? We want Almighty God to forgive us and to be lenient, compassionate and protective towards us. We therefore need to treat people in the same manner as well.
A destructive attitude is unacceptable for a Muslim. God says, “...speak to them with gentleness and generosity.” He says, “If you had been rough or hard of heart, they would have scattered from around you. “
If you want your words to be healing and instructive, you should be aware that the Qur’an has taken a lenient, gentle attitude as a basis. That means fair admonition, saying good words, approaching people with compassion; those are the commands of the Qur’an.
