TCR 120, 121 - the first parts of the real redemption was the conquest of the invasive hells and the ordering of the heavens

TCR 120 [2, 3]; 121[3]
If a person spends his time with thieves or pirates,
he ends up by becoming like them;
if he lives with adulterers and whores,
he ends up by thinking adultery of no consequence.
Again if he mixes with terrorists,
he ends up by thinking nothing of using violence on anyone.
All evils are contagious,
and can be likened to a plague which infects people
simply by their being exposed to the victims' breath;
or to a cancer or gangrene which spreads,
and makes first the surrounding parts,
and then those further and further away, rot,
until the whole body is destroyed.
It is the pleasures of evil,
to which everyone is prone from birth, that cause this.

. . . but for the redemption effected by the Lord
no one could be saved, nor could the angels remain unharmed

The . . . reason why the Lord redeemed the angels too
is that not only every man, but also every angel,
is held back from evil by the Lord and kept in a state of good.
For no one, whether angel or man,
is of himself in a state of good,
but all good is from the Lord.