How can one overcome recurring slips of the tongue and quick anger, avoid unintentional backbiting, and strive to speak in a way that pleases Allah, while feeling that the tongue can destroy life and harden the heart?

Insulting is describing another with words that denote defect and disdain. If the words make a person feel deficient or hurt, then they fall under the category of forbidden insults. To correct the tongue, one must occupy it with good deeds, such as reciting the Quran and engaging in remembrance (dhikr). One should also hold oneself accountable daily, proactively repent from the harms of the tongue, not despair of Allah's guidance, and busy oneself with one's own shortcomings rather than those of others.