The Two Witnesses that Zechariah saw are ministers of Christ who will be a big part at the end-time,

*Turning the hearts of the children to the fathers,
*Turning the hearts of the fathers to the children,

........Even though the Witnesses come with the ministry of judgment, they are ministers of mercy.

.....Their ministry in turning the hearts of the people back to God, stops the judgments, so that the earth is not struck with a curse.

Malachi 4:6
"And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse."