Excerpts from Dante’s Paradiso (Mandelbaum translation), Canto VII:
God had to pardon man, or of himself
man had to proffer payment for his folly
However, man could not pay for his sins.
. . . man lacked the power
to offer satisfaction by himself,
Thus, there was need for God, through His own ways,
to bring man back to life intact
But why did God not simply pardon man? Why the cross?
for God showed greater generosity
in giving His own self that man might be
able to rise, than if He simply pardoned;
for every other means fell short of justice,
except the way whereby the Son of God
humbled Himself when He became incarnate.
“For every other means fell short of justice.” The cross was necessary if God were to preserve His holiness in pardoning sinners.