This Salat means that the two Rak`ah are performed after the Adhan of Maghrib prayer but before the Fard Salat. This is elucidated by other Ahadith. Although this has the position of Sunnah Ghair Mu'akkadah, its importance is evident from the fact that the Prophet (PBUH) stressed it three times. Usually an order (Amr) signifies that the act is "essential" but here the decency embedded in the words "He who may so wish" has turned it to "desirable". In any case, inducement and stress of the Prophet (PBUH) on this Salat has left no room to doubt that it is desirable. Ahadith which follow lend further support to this contention.