St. Tikhon of Zadonsk, Journey to Heaven

Do we forgive our neighbors their trespasses? God also forgives us
in His mercy. Do we refuse to forgive? God, too, will refuse to
forgive us. As we treat our neighbors, so also does God treat us.
The forgiveness, then, of your sins or unforgiveness, and hence
also your salvation or destruction, depend on you yourself, man.
For without forgiveness of sins there is no salvation. You can see
for yourself how terrible it is.