This is the description of the believers from whom Allah has purchased their souls and wealth, who have these beautiful and honorable qualities.
{who repent} from all sins and shun all evils,
{who worship}, their Lord and preserve the acts of worship that include statements and actions. Praising Allah is among the best statements. This is why Allah said next,
{who praise (Him)}. Fasting is among the best actions, involving abstaining from the delights of food, drink and sexual intercourse, this is the meaning hereby,
{As-Sa'ihun (who fast)} [9:112]. Allah also described the Prophet's wives that they are.
{Saihat} [66:5], meaning, they fast. As for prostrating and bowing down, they are acts of the prayer,
{who bow down, who prostrate themselves,}

These believers also benefit Allah's creation and direct them to His obedience by ordaining righteousness and forbidding evil. They have knowledge about what should be performed and what should be shunned. This includes abiding by Allah's limits in knowledge and action, meaning, what He allowed and what He prohibited. Therefore, they worship the True Lord and advise creation. This is why Allah said next,
{And give glad tidings to the believers.}

since faith includes all of this, and the supreme success is for those who have faith.