which means: [Should you attempt to count your endowments from Allah, you would be unable.]
The tongue is one of many endowments Allah bestowed upon His slaves. Although the tongue is a tiny organ, the person who uses it to comply with the orders of Allah, the teachings of the Qur'an, and the teachings of the Prophet may earn blessings in this world and the in Hereafter. However, the one who uses his tongue in disobedience does not display thankfulness to Allah and leads to his own destruction. Certainly, being thankful to Allah means not using the endowments bestowed by Allah in what is forbidden.
One needs to know the sins of the tongue can be small or enormous.