The Prophet, may the peace and blessings of Allah be upon him, said: "The best of people are my generation; then those that come after them, then those that come after them." He (may the peace and blessings of Allah be upon him) also stated: "You shall not cease to be upon good for as long as there are amongst you those that sa w me and accompanied me. By Allah; you shall not cease to be upon good for as long as there are amongst you those that sa w those that sa w me and accompany those that accompanied me. By Allah; you shall not cease to be upon good for as long as there are amongst you those that sa w those that sa w those that sa w me and accompany those that accompanied those that accompanied me." 'Abdullaah bin Mas'ood (may Allah be pleased with him) who said: "Indeed Allah, The Most High, looked to the hearts of the servants; and so He found the heart of Muhammad (may the peace and blessings of Allah be upon him) to be the best of the hearts of the servants. So He chose him for Himself and sent him with His message. Then He looked to the hearts of the servants after the heart of Muhammad; and so He found the hearts of his (may the peace and blessings of Allah be upon him) Companions to be the best of the hearts. So He made them as viziers of His Prophet; that they should fight for His religion."
Biographies taken from the works of: Imaam adh-Dhahabee, Al-Haafidh Ibn Hajar, Ibn Al-Jawzee, Ibn Katheer, Imaam Ahmad bin Hanbal, Ibn Al-Atheer. May Allaah's Mercy be upon all of them.