Prophet Muhammad (peace be upon him) is the noblest descendent of Adam (peace be upon him). `Abdullaah ibn Salaam narrated that the Prophet (peace be upon him) said: I am the Sayyid of the descendents of Adam, with no boasting. (Related by Ibn Hibbaan in his Saheeh in this wording) Al-Tirmidee also related it with the addition “on the Day of Resurrection” before his saying “with no boasting.” The original Hadeeth, found in Saheeh Muslim, on the authority of ‘Aboo Hurayrah have the following wording: I am the Sayyid of the descendents of Adam on the Day of Resurrection. I am the first for whom the grave will be opened. I am the first to intercede and the first whose intercession will be accepted.
According to Al-`Iz: the Arabic word “Sayyid” means a person who is characterized by the highest moral qualities and ethical standards.This implies that Prophet Muhammad (peace be upon him) is the best of humanity both in this world and the hereafter. In this world, because of his exceptional moral virtues and excellence of character. In the hereafter, superiority of reward is proportionate to virtues and nobility of manners. Since he (peace be upon him) excelled them all in this world, he will have a higher status and degree of honor than all others in the hereafter… read more here.