Weak
graded by Al-Albani
Mishkat al-Masabih 6124
وَعَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ يَوْمَئِذٍ يَعْنِي يَوْمَ أُحُدٍ: «اللَّهُمَّ اشْدُدْ رَمْيَتَهُ وَأَجِبْ دعوتَه» . رَوَاهُ فِي «شرح السّنة»
Sa`d b. Abu Waqqas told that God's messenger said that day, i.e., the day of Uhud, "0 God, strengthen his shooting and answer his supplication." It is transmitted in Sharh as-sunna.
Cited in Mishkat al-Masabih (No. 6124).