emprise > undertaking, enterprise
5 That none did other's safety despise,
That > [So that] other's > (Or: "others'") despise > treat as valueless
6 Nor aid envy to him, in need that stands,
envy to > begrudge
7 But friendly each did other's praise devise
praise > praiseworthiness; virtue devise > contrive, scheme
8 How to advance with favourable hands, 9 As this good prince redeemed the Redcross Knight from bonds.
As > [Just as]
109.2