Both Uses of

redeem

in

Frankenstein - 1831 version

He tried to make us act plays and to enter into masquerades, in which the characters were drawn from the heroes of Roncesvalles, of the Round Table of King Arthur, and the chivalrous train who shed their blood to redeem the holy sepulchre from the hands of the infidels.
p. 39.3 *

redeem = regain possession

Thus not the tenderness of friendship, nor the beauty of earth, nor of heaven, could redeem my soul from woe; the very accents of love were ineffectual.
p. 96.9 *

redeem = save

Definitions:

(1) (redeem as in: its main redeeming quality is...)
to make up for something bad; or to save
(2) (redeem as in: redeem the coupon)
exchange, convert, or pay off
The exact meaning of redeem can depend upon its context. For example:
- "to redeem a coupon" -- exchange something for something else of value
- "to redeem stock" -- sell or convert to cash
- "to redeem a mortgage" -- pay off a loan
(3) (meaning too rare to warrant focus)
In Christianity, redemption is used to reference Jesus' sacrifice to make up for human sin.

Old usage (as might be found in the Bible or in Shakespeare) also uses redeeming time to refer to making the best use of time.