How does original sin affect mankind according to the Bible?

According to Scripture, as elaborated in Romans 5:12, original sin entered through Adam, leading to the imputation of sin to all humanity. This means every person is born with a sinful nature, inclined to sin from birth. John states plainly that claiming we have no sin is to make God a liar (1 John 1:8). Every human is conceived in iniquity and, without the work of sovereign grace, remains dead in trespasses and sins, unable to seek God or choose righteousness. The recognition of original sin is fundamental for understanding the necessity of divine grace for salvation.