Is simply making the intention in one's heart for an act of worship, such as the worshipper saying to himself, "Now I will pray Maghrib," sufficient, and what should one do if he forgets a prostration from the prostrations of forgetfulness (sujud al-sahw) and then says the taslim?

It is sufficient for the worshiper to intend in his heart to perform the prayer he is about to offer, just as he intends to begin the Dhuhr or Asr prayer. Uttering the intention, such as saying, "I will pray Maghrib," is not prescribed. As for someone who forgets one of the prostrations of forgetfulness (sujood al-sahw), his ruling has been clarified in previous fatwas.