All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

The Arabic language itself-along with the Arabic disconnected letters-if they are not part of sacred names or writings in Islamic Sharia such as the names of Allah, the prophets, angels, the words of Allah, or the words of His messenger, do not inherently possess sanctity. Therefore, it is permissible to write them on utensils, tools, or on the ground for a legitimate purpose, such as teaching students. Ibn Hajar al-Haytami, a Shafi'i scholar, stated: "It is clear that letters themselves are not respected." (Tuhfat al-Muhtaj, Vol. 1/P. 178).

In conclusion, there is no sin in writing Arabic letters on the ground for a considerable purpose in Sharia, such as teaching students those letters. And Allah the Almighty knows best.