All human beings are considered sinners because, according to the Orthodox understanding, sin is inherited from Adam, which signifies the transmission of an originally corrupted, sinful nature.

Inherited Corruption: Theological Roots of Sin and Suffering

All human beings are considered sinners because, according to the Orthodox understanding, sin is inherited from Adam, which signifies the transmission of an originally corrupted, sinful nature. In source link txt it is stated:
"The Orthodox Eastern Church has always understood original sin as that 'aphid seed,' that hereditary corruption of nature and predisposition to sin which all people receive from Adam through birth. Conception and birth are the channels through which the ancestral corruption is transmitted... Therefore, humanity, corrupted at its root, must inevitably be corrupted in its branches. And if the first human became sinful and damaged his entire nature, then his offspring cannot help but inherit that same sinful and damaged nature."

This inheritance of corruption implies that no person can have a completely pure spiritual nature – as is additionally emphasized in source link txt, which underlines that "All humans, as descendants of fallen Adam, are prone to sin," referring to sacred texts that affirm universal human sinfulness.

Regarding the impact of this condition on suffering, the corrupted human nature gives rise to internal and external conflicts, leading to suffering. In source link txt it is explained:
"For if every being acts hostilely towards others and displaces them with its own force, then others respond with the same hostility, crowding it out, and it inevitably must experience this hostile impact. Such a trial is suffering – the second type of worldly evil... Just as everything in nature sins against one another, inevitably one suffers from another."

Thus, inherited sinfulness results in people not only bearing a corrupted nature within themselves but also living in a world where their relationships are filled with hostility and rejection. This creates the persistent suffering that stems from an internal and external struggle rooted in original sin.

Supporting citation(s):
"The Orthodox Eastern Church has always understood original sin as that 'aphid seed,' that hereditary corruption of nature and predisposition to sin which all people receive from Adam through birth. Conception and birth are the channels through which the ancestral corruption is transmitted..." (source: link txt)

"For if every being acts hostilely towards others and displaces them with its own force, then others respond with the same hostility, crowding it out, and it inevitably must experience this hostile impact. Such a trial is suffering – the second type of worldly evil... Just as everything in nature sins against one another, inevitably one suffers from another." (source: link txt)