Chapter 2, Verse 238, The Cow
سُوۡرَةُ البَقَرَة
حَٰفِظُواْ عَلَى ٱلصَّلَوَٰتِ وَٱلصَّلَوٰةِ ٱلۡوُسۡطَىٰ وَقُومُواْ لِلَّهِ قَٰنِتِينَ
Guard strictly (five obligatory) As-Salawat (the prayers) especially the middle Salat (i.e. the best prayer - 'asr). And stand before Allah with obedience [and do not speak to others during the Salat (prayers)].
Chapter 33, Verse 42, The Coalition
سورة الأحزاب
وَسَبِّحُوهُ بُكۡرَةٗ وَأَصِيلًا
And glorify His Praises morning and afternoon [the early morning (Fajr) and 'asr prayers].
Chapter 38, Verse 32, Sad
سورة ص
فَقَالَ إِنِّيٓ أَحۡبَبۡتُ حُبَّ ٱلۡخَيۡرِ عَن ذِكۡرِ رَبِّي حَتَّىٰ تَوَارَتۡ بِٱلۡحِجَابِ
And he said: "Alas! I did love the good (these horses) instead of remembering my Lord (in my 'asr prayer)" till the time was over, and (the sun) had hidden in the veil (of night).
Chapter 76, Verse 25, The man
سورة الإنسان
وَٱذۡكُرِ ٱسۡمَ رَبِّكَ بُكۡرَةٗ وَأَصِيلٗا
And remember the Name of your Lord every morning and afternoon [i.e. offering of the Morning (Fajr), Zuhr, and 'asr prayers].
Chapter 103, Verse 1, The declining day
سورة العصر
وَٱلۡعَصۡرِ
waalaaasri
By Al-'asr (the time).