Silsilat al-Ahadith al-Sahihah

Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that among the beautiful women, there was an extremely beautiful woman who used to pray behind the Prophet (peace and blessings be upon him). Some men used to pray in the last rows so that they could see her, and they would look at her from under their armpits during bowing (ruku‘), while some people would move forward and stand in the first row so that they would not see her. Allah Almighty revealed this verse (to describe the behavior of both): "We surely know those of you who go forward and those who lag behind." (Surah Al-Hijr: 24)