The process of restoration between sinful humanity and God begun at the Cross.
Revelation 5: 8-9 - Now when He had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each having a harp, and golden bowls full of incense, which are the prayers of the saints. 9 And they sang a new song, saying:

“You are worthy to take the scroll,
And to open its seals;
For You were slain,
And have redeemed us to God by Your blood
Out of every tribe and tongue and people and nation,