I. To the Question

7. There are two difficulties here: one, how the blessed are incapable of sin, and the other how Christ, who was a wayfarer and was able to merit, could have, along with the blessed, inability to sin. The first article belongs to 4 d.49, about which see there [q.6 nn.10-11].

8. To the second question I reply in brief that since Christ in the first moment of the [hypostatic] union was blessed with God, his blessedness took from him all the power of sinning that could be taken from him by blessedness, although along with it there stood, by dispensation, the power of meriting; for the fullness of glory, whereby he was no less joined to the end (though he could merit) than any other blessed, as equally removed all power in him for turning away from the end as it does in others.

9. In agreement with this is that when matter is under a form equal to its whole appetite it cannot be under another form (the point is plain in the case of all the celestial bodies); of such sort is blessedness with respect to the soul, as is plain from the definition of blessedness in Augustine On the Trinity 13.5 n.8, “He is blessed who both has all that he wills and wills nothing badly;”     therefore etc     .

10. Those, however, who say [Henry of Ghent; cf. d.2 n.14 above] that Christ’s united nature enjoyed the end by force of the union have to say as a result that he was incapable of sin not only by his fullness of glory but by the force of the union.

11. This opinion was refuted above [d.2 nn.15-23].