Evil is a mind set for sin to take place. Evil is unrightousness, evil cause one to sin, So in a sense evil is sin, because in 1 John 5: 17 says: All wrongdoing is sin, and there is sin that does not lead to death
The sins that do not lead unto death are hidden or secret faults (Psalm 19:12) or unintentional sins (Leviticus 4:2-3) falling short of the glory of God (Romans 3:23) and sins that are confessed (1 John 2:1) (1 John 1:9). For when a brother struggles with a specific sin, they can have another fellow brother pray to give them "life" (success over sin) in this area. For 1 John 5:16 says, if any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. For a Christian can even see another brother committing unintentional sin and or not being perfect before our Lord. This brother can help to give them "life" to overcome these sins that do not lead unto death.
But even unintentional sin needed to be taken to the priest and cleansed. It was still evil to a Holy and pure God. That is why Jesus Christ came. To take away the sins of the entire world. So that when a baby dies, the sin from Adam passed down to them by the male seed is not imputed to them. For Jesus paid the price for all sin and can only be forgiven for those who are innocent and or righteous in the fact that they repent of their sins and accept Jesus Christ (Thereby putting on the robe of righteousness).