Grace presupposes predestination:
Thoughts from Augustine of Hippo
Augustine's doctrines of sin and grace are inseparable from his doctrines of predestination and perseverance.
Since man is dead in trespasses and sins, he is completely dependent upon God's initiative. "There is none that seeks after God; all have turned aside, there is none that does good, not even one." Such is the prognosis of man, man apart from God.
But in grace, it pleased God to reach down, to condescend to man, to command life unto him, just as he commanded light by the word of his power, "Let there be light." God makes himself known to man, through the mediatorship and redemption wrought by his Son, applied by the Spirit.
Evidently, not everybody is enjoying this high privilege. How come? What makes man to differ from another? Is it anything in him? Not at all. "One can receive nothing except it be given him from heaven" (John 3:27). "What have you that you have not received?" (1 Corinthians 4:7). A simple but devastating questions that admits of one answer: “We Christians have received everything.” All is of grace! But if it is of grace, then it is bestowed and shown to particular persons.
But is grace given because of anything done by man? Is it given because he believes? Quite the contrary! Our faith, our good works, our repentance, anything good that we do, we do it by the grace of God operating in us. We love God because he loved us first. He did not love his own because he foresaw something good or commendable in them. Believers were at one time children of wrath, like the rest of mankind (Ephesians 2:1ff). All Christians were at one time disobedient, rebellious, lost, God-haters, like the others.
Then what makes the difference? According to Augustine, and before him pre-eminently the Apostle Paul (Romans 9-11), it is because of God's love in predestinating those who should be saved. This is the fountainhead of all blessings, including the ineffable blessing of salvation itself. God manifests his grace, but grace is selective, "I will show mercy to whom I will show mercy, and will show compassion to whom I will show compassion." "Jacob I have loved, but Esau I have hated." Why so? Because God, the sovereign God, has the exclusive right to draw unto himself those he desires, having chosen them in Christ Jesus before the foundation of the world, having bestowed grace upon them from eternity (2 Timothy 1:9). Man has no right whatsoever to God's grace; if man can appeal to God for anything, it is only his condemnation that he can legitimately ask for. Nothing else: man has forfeited every right to any divine blessing. "God has consigned all men to disobedience that he might have mercy upon all."
So if God brings salvation to particular persons, then it means to God is determined to bring those persons to glory. "His gifts and his calling are without repentance." The Bible teaches that there is an unbroken and infallible chain of blessings reserved for God's elect. Those he foreknows (loves beforehand) he predestines and eventually calls and sanctifies and glorifies. No exceptions. "He who began a good work in you will complete it until the day of Christ." "I give them eternal life and they shall never perish."
Since God predestines (and his purpose is never thwarted) he also necessarily preserves his own. "The Lord knows them that are his." "We are kept by the power of God through faith unto salvation." If any one of the elect, even one, fails to reach glory, then God's predestination is dependent upon the creature and therefore fallible.
But Augustine rightly asserted that salvation, from beginning to end, is God's sole accomplishment. In asserting this Augustine said nothing novel; Jonah’s testimony was virtually the same: "Salvation is the Lord's." In its conception (in eternity), its accomplishment (Christ's coming, particularly his death and resurrection), and its application in time (to particular persons, by the Spirit, to bring them to faith), it is God's work for man and in man: God working in us both to will and to do according to his good pleasure.
Sinful man needs grace first and foremost; grace is given selectively, because God has already determined who will be partakers of Christ, and those who are appointed to eternal life not only believe but continue to the end. Thus the sinner, as Augustine explains it, is constantly cast upon the grace of God. The same almighty power which converts him is needed to keep him, and that alone infallibly secures him everlasting redemption.
If Augustine was correct in these affirmations, why has the church largely abandoned the heritage he left her? When we hold on to God’s predestination, we magnify his grace. In this we are humbled and, rightly believed, we become increasingly grateful to God who did marvellous things on our behalf.
In following Augustine in this matter we follow Paul, and in following Paul we follow Christ.