[So be patient; indeed, the promise of Allah is truth], meaning: that which He promised to give him in the Hereafter, and to give to those who believed in Him. [And ask forgiveness for your sin, and glorify with the praise of your Lord in the evening and the early morning]. This was the prayer of Makkah before the five prayers were made obligatory, at the time when prayer was two rak'ahs in the morning and two rak'ahs in the evening.

Tafsir of Surah Ghafir from verse 56 to verse 58.