I used to greet the Prophet (ﷺ) while he was in prayer and he would return my greeting, but when we returned (from Ethiopia) I greeted the Prophet (while he was praying) but he did not return the greeting, and (after finishing the prayer) he said, "In the prayer one is occupied (with a more serious matter)."
Actions while Praying - Sahih al-Bukhari 1216
This narration from Abdullah ibn Mas'ud (may Allah be pleased with him) demonstrates the evolution of Islamic rulings regarding speech during prayer. Initially, the Prophet ﷺ would respond to greetings while praying, but this practice was later abrogated when the prayer was fully established and its sanctity emphasized.
Legal Ruling (Hukm)
The final ruling established by this hadith is that speaking during obligatory prayers invalidates them, as the Prophet ﷺ explicitly stated "In the prayer one is occupied with a more serious matter." This indicates complete absorption in divine communication.
Scholars differentiate between obligatory (fard) and voluntary (nafl) prayers regarding incidental speech, with stricter rules applying to obligatory prayers.
Spiritual Significance
The prayer is a sacred conversation between the servant and Allah. External speech disrupts this spiritual connection and diminishes the required presence of heart (khushu').
The Prophet's ﷺ explanation emphasizes that the worshipper is engaged in the most important matter possible - standing before the Lord of the Worlds.
Practical Application
If greeted during prayer, one should not respond verbally. The greeting should be acknowledged after completing the prayer.
This ruling applies to all forms of unnecessary speech during prayer, except for specific cases like correcting the imam's recitation or warning of danger.