The difference between a stressed and non-stressed Sunnah

Q 1: What is the difference between stressed and unstressed Sunnah (supererogatory act of worship following the example of the Prophet)? Are we obligated to observe only the stressed acts of Sunnah, or all acts, whether they are stressed and unstressed? Some people may refrain from observing a specific act of Sunnah on the pretext that it is not stressed. Please advise, may Allah reward you with the best.

A: The stressed Sunnah denotes every supererogatory act of worship which the Messenger (peace be upon him) urged Muslims to observe, such as Salat-ul-Kusuf (Prayer at the time of a solar eclipse), Witr (Prayer with an odd number of units), Salat-ul-Duha (supererogatory Prayer after sunrise), and Al-Sunan Al-Rawatib (supererogatory Prayers that were stressed and regularly performed by the Prophet) which we should observe, because Ibn `Umar (may Allah be pleased with him and his father) said: I learned from the Messenger of Allah (peace be upon him) performing two (supererogatory) Rak`ahs (units of Prayer) before Zhuhr (Noon) Prayer and two after it, two Rak`ahs after Maghrib (Sunset) Prayer, two Rak`ahs after `Isha' (Night) Prayer, and two Rak`ahs before Fajr (Dawn) Prayer. Also, `Aishah (may Allah be pleased with her) said: The Prophet (peace be upon him) never used to omit offering four Rak`ahs before Zhuhr Prayer. (Related by Al-Bukhari in his Sahih) These acts of Sunnah make up for any shortfalls in the Five Obligatory Daily Salahs. Therefore, it is Mustahab (desirable) for Muslims to perform all acts of Sunnah reported from the Prophet (peace be upon him) as much as they can, following the Hadith Qudsy (Revelation from Allah in the Prophet's words) which states: My slave continues to draw closer to Me through supererogatory acts of worship until I love them... However, these acts of stressed Sunnah are not obligatory. They are voluntary, and there is no sin on anyone who does not observe them. (Part No. 4; Page No. 9) May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.