What is the ruling on praying the Sunnah four rak'ahs before and after Dhuhr, and four rak'ahs before Asr, and is it valid if prayed two rak'ahs at a time, or four continuous rak'ahs? And is the intention to pray the Sunnah valid for the non-emphasized rak'ahs? And is it permissible to pray Witr one rak'ah without the Shafa' (even-numbered rak'ahs) after the 'Isha prayer and its two Sunnah rak'ahs?

It is preferable for supererogatory prayers to be two rak'ahs with a tasleem, though it is permissible to perform four rak'ahs with one tasleem. It is also permissible to perform four rak'ahs before Dhuhr and four after it, and four before Asr. This is from the Sunnah, as the Prophet, peace and blessings be upon him, said: "Whoever prays four rak'ahs before Dhuhr and four after it, the Fire shall not touch him." As for the intention for Sunnah prayers, timed supererogatory prayers and those with specific causes require the intention to perform the prayer along with its designation. However, for absolute supererogatory prayers, it suffices to simply intend to perform the prayer.