Luke 1:16-17

16He will turn many of the sons of Israel back [from sin] to [love and serve] the Lord their God.

17It is he who will go as a forerunner before Him in the spirit and power of Elijah, to turn the hearts of the fathers back to the children, and the disobedient to the attitude of the righteous [which is to seek and submit to the will of God]—in order to make ready a people [perfectly] prepared [spiritually and morally] for the Lord.”