If a person believes that God knows about his life, both the apparent and the secrets, then such a person will always say the right word when he speaks about someone. Otherwise, he will stay quiet. This is the meaning of the hadith. The belief that God knows the hidden and the apparent of my life will stop you from speaking badly about someone, at home or in society. The option before us is to either speak nicely of others or remain silent.
According to a hadith: وَمَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَاليَوْمِ الآخِرِ فَلْيَقُلْ خَيْرًا أَوْ لِيَصْمُتْ (Sahih al-Bukhari 6018) A person has two option: either speak or remain silent. While speaking one should say what the Quran or the Prophet have enjoined on us. This means one should speak appropriately or remain silent. The third option is of speaking anything one wants. In any situation that we face, we shouldn’t just say whatever comes to our mind. We don’t have this option. We should either remain quiet, or say what the Quran and Hadith contain.
The Quran and Hadith tell us about God's message. They are guidebooks. The Quran guides us about everything. تِبْيَانًا لِكُلِّ شَيْءٍ، وَتَفْصِيلًا لِكُلِّ شَيْءٍ (16:89, 6:154) The Quran makes everything clear. Some people give a strange interpretation of this. They claim the Quran speaks of technology, science, philosophy, etc. This is wrong. It is wrong to say that the Quran speaks about the technology of building a car or aeroplane, or how to run modern industry. All this is wrong.
تِبْيَانًا لِكُلِّ شَيْءٍ، وَتَفْصِيلًا لِكُلِّ شَيْءٍ doesn’t mean that the Quran contains details of everything. The Quran contains guidance related to salvation, the Hereafter, and divine character. These are subjects of the Quran. If a person says he believes the Quran to be the word of God, it becomes incumbent on him to take guidance from the Quran in every matter.
