Authentic Supplication Number 16.

Allah The Exalted said:

“O you who believe! Remember Allah, with much remembrance; And glorify Him morning and ‘Aseela” (20).

“And do bring Thy Lord to remembrance in your soul, with humility, and remember without loudness in words, in the morning and ‘Asal and be not of those who are unheedful” (21).

“And sabbih (22) in praise of Your Lord in the evening and in the morning” (23).

“And sabbih in praise of Your lord, before the rising of the sun and before the setting” (24).

“Send not away those who call on their Lord in the morning and the evening” (25).

“He told them by signs to make Tasbeeh in the morning and in the evening” (26).

“And of the night also make Tasbeeh of Your Lord and at the setting of the stars” (27).

“So subhana ‘allahi when you reach eventide and when you rise in the morning” (28).

“And establish [regular] prayers at the two ends of the day and Zulufan (29) of the night.”

The Prophet ┬ásaid: “Whoever would say as he enters upon morning and as he enters upon evening:

“Subhana ‘allahi wa bihamdihi (30) 100 times, no one would arrive on the Day of Resurrection with better than what he arrived with, except for a person who said the same, or more (31).”

(20) ‘Aseela refers to the time after ‘Asr and before Maghrib. Surah ‘Al-Ahzab (#33) Vs. 41-42.
(21) Surat Al-‘A`raf (#7) V.205.
(22) Sabbih is a command to make tasbeeh which means to say suhhana ‘allah see footnote 8.
(23) Surat Ghafir (#40) V-55.
(24) Surat Qaf (#50) V.39.
(25) Surat ‘Al-‘An`am (#6) V.52.
(26) Surat Maryam (#19) V.11.
(27) The setting of the stars: the glorious hour of early dawn. Surat At-Toor (#52) V.49.
(28) Surat ‘Ar-Room (#30) V.17.
(29) Zulufan is the plural for Zulfah which is a portion of the night, thus referring to the Maghrib and `Isha’ prayers. Surat Hood (#11) V.114.
(30) I honor Allah from all things unsuitable to Him and [I am] in celebration of his Praise.
(31) Or more: of utterances like La ‘ilaha ‘illa ‘allah and other legislated sayings. He should not bind such sayings by any number that has not be legislated.

Reported by Muslim. Al-Albani included this hadeeth in The Authentic of Good Sayings as #16.