Shaykh Dr. Abdur Rahman Freywai
Explanation:
1:
That is, do not imitate the Jews, Christians, or disbelievers in any of their actions.
Especially in these two characteristics of greeting, it is possible that these people, instead of saying (as-salamu alaykum) and (wa alaykum as-salam), would suffice with only a gesture.
To greet with the tongue is the Sunnah of the Prophets.
Therefore, by adopting this Sunnah, if in cases of excuse, gesture is also included, then there is no harm in it—
such as greeting a deaf person, etc.
Similarly, in some specific situations, sufficing with only a gesture is also correct—
such as a mute person giving salam, or responding with a gesture during the prayer, etc.
Note:
(Based on corroborating narrations and supporting evidence, this hadith is hasan (good).
Otherwise, its narrator “Ibn Lahi‘ah” is weak,
and the narration from him by ‘Abdullah ibn al-Mubarak is mawquf (stopped at the Companion).
For details, see al-Sahihah, no. 2194.)
Source: Sunan al-Tirmidhi – Majlis ‘Ilmi Dar al-Da‘wah, New Delhi Edition, Page: 2695