In Orthodoxy, sin is called a serious transgression of man, leading to the destruction of the human soul, the impossibility of eternal life in the kingdom of God. Almost all sins can be atoned for in confession.
Unforgivable sin
There is one sin that will forever close the door to the kingdom of God - the expression of discontent and the condemnation of his actions. The Orthodox Christian should always remember this and not make a fatal mistake. This sin is called pride and is considered original. According to the Bible, Lucifer was expelled from heaven to earth precisely because he dared to express dissatisfaction with the existing order.
