Allah will bring out from concealment al-Mahdi from my family and just before the day of Judgment; even if only one day were to remain in the life of the world, and he will spread on this earth justice and equity and will eradicate tyranny and oppression.
(Musnad Ahmad Ibn Hanbal, Vol. 1, P. 99)

sister 'Aisha the hadeeth is indeed Abu dawood wallahu a3lam .