Commentary
Based on the authority of some ahadith, a very large number of ` ulama', have said that al-salat al-wusta َالصَّلَاةِ الْوُسْطَىٰ or the middle salah is the salah of ` Asr because there are before it, two Salahs during the day, that of Fajr and Zuhr; and after these come two evening Salahs, that of Maghrib and ` Isha'. Special emphasis has been placed on it because this is a time in which most of the people are busy in their professional work.
Incidentally, the Qur'anic word, Qanitin قَانِتِينَ meaning obedient or submitting, rendered here as 'stand before Allah in total devotion', has been explained in Hadith as denoting sukut سکوت or motion-less silence.
It was through this very verse that talking in salah was forbidden. Earlier, talking was permissible. The verse 239 has allowed a special way of offering prayers in the state of 'fear' i.e. the state of war. In such a state, one can offer salah نماز (prayer) while standing, with a condition that he can stand in one place without moving, and can make the gesture of sajdah سجدہ in a lower position than he makes in ruku' رکوع . However, salah cannot be performed while walking. If it is not possible to perform the prayer in the said manner, such as at the time of actual fighting, then, it is permissible to delay the prayer and to offer it later as qada' قضاء .