Is the Sunnah Prayers obligatory like the five daily Prayer?

Q;Somebody said if we don't offer the Sunnah prayers then Fard prayers are not accepted. Is this correct? A;All-Praise is due to Allah, The five daily Prayers are obligatory upon every Muslim who is mature, and sound in mind (sane) and their are to people that are excused from the five daily Prayers and they are the Haaidah (the women who has her periods) and the nifaas (the post-natal bleeding period). As for any other prayer besides the prescribed five daily Prayers are considered voluntary. Evidently this is proven through the Hadith of Al-Bukhaari (46) and Muslim (110) narrated that Talhah ibn ‘Ubayd-Allaah said: A man came to the Messenger of Allaah (peace and blessings of Allaah be upon him) and when he drew close to him he asked him about Islam. The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Five prayers each day and night.” He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” And the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “And fasting Ramadaan.” He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” And the Messenger of Allaah (peace and blessings of Allaah be upon him) told him about zakaah. He said: “Do I have to do anything else?” He said: “No, not unless you do it voluntarily.” The man left, saying, “By Allaah, I will not do any more than this or any less.” The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “He will succeed, if he is speaking the truth.” Al-Nawawi said: This is to be understood as meaning that he did not offer naafil prayers and he did not omit any of the obligatory prayers. Such a person will undoubtedly be successful, even though his persisting in not offering Sunnah prayers is something blameworthy for which his testimony is to be rejected. But he is not sinning thereby, rather he will be successful and will attain salvation. Sharh Muslim, 1/121 As explained in the Hadith that Muslims are obliged to Pray the five daily Prayers and every thing else is considered voluntary. And Allah knows best...