First of all, it is highly recommended to perform Witr, as it was practiced by the Prophet (peace and blessings be upon him) and he encouraged Muslims to practice it. However, it is not compulsory to offer Witr prayer according to the majority of scholars. Only Imam Abu Hanifah sees that it is obligatory or wajib (but it is according to him less in obligation than the other five daily prayers which are fard). It is rather a confirmed Sunnah that Muslims are highly recommended to offer.
Sheikh `Atiyyah Saqr, former head of Al-Azhar Fatwa Committee, states that: “Imam Abu Hanifah is of the opinion that Witr prayer is wajib (obligatory). As for the majority of Muslim scholars, they opine that Witr is a highly recommended Sunnah. So, this means that performing Witr is required in all Madh-habs (Schools of Fiqh), but the degree of this requirement is stronger according to Abu Hanifah than according to other scholars. Also, it indicates that negligence of performing Witr prayer, according to Imam Abu Hanifah, renders one (the negligent person) accountable before Allah for his negligence. He based his ruling on the hadith of the Prophet (peace and blessings be upon him) who is reported to have said: “Witr is a right that a servant of Allah owes to his Lord, so, the one who does not perform Witr does not belong to me, i.e., doesn’t follow my sunnah.”
According to other scholars, neglecting Witr is not like neglecting the prescribed (obligatory) prayers, i.e., neglecting it will not go to the extent that it will render one accountable before Allah in the same way as he will be held accountable for neglecting the prescribed (obligatory) prayers. Yet, it is highly recommended because the Prophet (peace and blessings be upon him) used to observe it. But it is not obligatory like the five obligatory prayers. For the Prophet (peace and blessings be upon him) answered the one who asked him how many prayers Almighty Allah made obligatory on him saying: “Allah has prescribed five prayer in the day and the night.” The questioner said, “Am I obliged to do more?” He said: “No, unless you perform supererogatory prayers.” The man went away saying: “By Allah, I will not increase or decrease beyond these obligatory prayers.” Then, the Prophet (peace and blessings be upon him) said, “He would succeed if he did what he said.” (Reported by Muslim)”