Reference : Hisn al-Muslim 75a

الْحَمْدُ لِلَّهِ وَحْدَهُ،
وَالصَّلاَةُ وَالسَّلاَمُ عَلَى مَنْ لاَ نَبِيَّ بَعْدَهُ
Alḥamdulillahi waḥdah
waṣ-ṣalatu was-salam `alā man lā nabiyya ba`dah.


All praise is due to Allah alone, 
and peace and blessings be upon him after whom there is no other Prophet.

Reference:
Anas (RA) said that he heard the Prophet (ﷺ) say: "That I sit with people remembering Almighty Allah from the morning (Fajr) prayer until sunrise is more beloved to me than freeing four slaves from among the Children of Isma'il. That I sit with people remembering Allah from the afternoon ('Asr) 
prayer, until the sun sets, is more beloved to me than freeing four slaves from among the Children of Isma'il." This was reported by Abu Dawud (no. 3667). Al-Albani graded it good in Sahih Abu Dawud 2/698.

Chapter: In the morning and evening