some of his foremost disciples, who cited this hadith as unequivocal proof, even though they all concur that the preferred place for a single follower is on the imam’s right.

Lessons derived from the hadith:
1- The optimal position for a lone follower is to stand to the imam’s right.
2- A follower’s prayer is still valid if he stands to the imam’s left while the right side is vacant, since the Prophet ﷺ did not invalidate Ibn Abbas’s prayer.
3- If the lone follower begins on the imam’s left and then shifts to his right, he should move behind the imam, as one wording of the hadith recorded by al-Bukhari states.
4- Movements within the prayer that are required for its correctness do not invalidate it.
5- It is permissible for a young boy to line up alone beside an adult.
6- Night prayer is legislated and recommended.
7- The diligence of Ibn Abbas (may Allah be pleased with him) and his eagerness to acquire and verify knowledge.
8- For the validity of leading the prayer, it is not a condition that the imam intend beforehand to act as imam.