Augustine clearly taught unconditional election; it did not originate with Calvin. They both rejected the teaching of conditional election, that God elects people because he foresaw faith in them. Furthermore, both Calvin and Augustine found unconditional election in Scripture. Here are Augustine’s comments on John 15:16 (You did not choose Me but I chose you – NASB):
Ineffable grace! For what were we before Christ had chosen us, but wicked, and lost? We did not believe in Him, so as to be chosen by Him: for had He chosen us believing, He would have chosen us choosing.
This passage refutes the vain opinion of those who say that we were chosen before the foundation of the world because God foreknew that we should be good, not that He Himself would make us good.
For had He chosen us because He foreknew that we should be good, He would have foreknown also that we should first choose Him, for without choosing Him we cannot be good; unless indeed he can be called good who hath not chosen good.
What then hath He chosen in them who are not good? Thou canst not say, ‘I am chosen because I believed’; for hadst thou believed in Him, thou hadst chosen Him. Nor canst thou say, ‘Before I believed I did good works, and therefore was chosen.’ For what good work is there before faith?
What is there for us to say then, but that we were wicked, and were chosen, [so] that by the grace of the chosen we might become good?
This quote can be found in Nicene and Post-Nicene Fathers 1.7, tractate LXXXVI.
Covenant Presbyterian Church (OPC)