وَلَا تَمْشِ فِي الْأَرْضِ مَرَحًا ۖ إِنَّكَ لَن تَخْرَقَ الْأَرْضَ وَلَن تَبْلُغَ الْجِبَالَ طُولًا

Qatada, one of the early commentators of the Quran, said, ‘Don’t say, “I have seen” when you have not seen, don’t say, “I have heard” when you have not heard, and don’t say “I know” when you do not know.’ One who fears to be called to account before God, will never say anything without first verifying it. Man should use his eyes, ears and brain for the purpose they were designed and should talk of and act only upon such matters for which there is adequate evidence to warrant this. He should eschew all that is baseless, for example, bearing false witness, making false allegations, condemning someone on the basis of hearsay, justifying falsehoods merely on account of envy, placing credence on things that man does not know for sure because of his limitations. The ears, eyes and mind are apparently under man’s control. But these are, as it were, entrusted to him by God, and so it is a must for a man to utilize them according to God’s will, otherwise he will be taken strictly to task for their misuse. Man, even with all the power given to him, cannot tear apart the ground on which he lives, while the sheer height of the mountains negates his every claim to greatness. This is a practical comparison illustrating the real status of man as opposed to the greatness of God. It emphasizes the fact that man should not be filled with pride in this world. He should tread the path of humility and submissiveness and not that of pride and rebellion.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (17:37)