For the gifts and calling of God are unchangeable.
All Commentaries on Romans 11:29 Go To Romans 11
Augustine of Hippo
AD 430
For God to order his future works in his foreknowledge, which cannot be deceived or changed, is entirely (and nothing other than) to predestine. But just as he whom God has foreknown to be chaste, although this may be unclear to him, acts in such a way as to be chaste, so he whom God has predestined to be chaste, although this may be unclear to him, does not, simply because he hears that by God’s gift he will be what he will be, fail to act so as to be chaste. Indeed, his charity is delighted, and he is not puffed up as if he had not received it. Not only is he not hindered from the work of charity by the preaching of predestination, but on the contrary he is helped in this task, so that when he glories he may glory in the Lord.