Luke 1:17

And he will [himself] go before Him in the spirit and power of Elijah, to turn back the hearts of the fathers to the children, and the disobedient and incredulous and unpersuadable to the wisdom of the upright [which is the knowledge and holy love of the will of God]–in order to make ready for the Lord a people [perfectly] prepared [in spirit, adjusted and disposed and placed in the right moral state]. [Isa. 40:3; Mal. 4:5, 6.]