Metellus Numidicus was elected censor in 102 BC in partnership with his cousin Gaius Caecilius Metellus Caprarius. During the censorship, he tried to expel Marius' ally Lucius Appuleius Saturninus from the Senate, but without success. Afterwards, Saturninus had his revenge when, having been elected tribune of the plebs, he and Marius proposed an agrarian law awarding land to Roman veterans, with an additional clause that obliged every Senator to swear allegiance to the agrarian law, under penalty of expulsion from the Senate and a heavy fine. In the Senate, Marius first declared that he would never take the oath, in which Metellus seconded him; in the event, however, Marius and all other senators but Metellus took the oath. Rather than swear obedience to a law he opposed, Metellus Numidicus resigned his Senate seat and paid the corresponding fine. After leaving the Forum, he said to his friends: