Augustine of Hippo
Catena Aurea · Johannesevangelium 15
This is my commandment, That ye love one another, as I have loved you. Greater love hath no man than this, that a man lay down his life for his friends. Ye are my friends, if ye do whatsoever I command you. Henceforth I call you not servants; for the servant knoweth not what his Lord doeth: but I have called you friends; for all things that I have heard of my Father I have made known unto you. Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you. But I have called you friends, for all things that I have heard of My Father, I have made known unto you.
(de Prad. Sanct. c. xvii.) They are chosen then before the foundation of the world, according to that predestination by which God foreknew His future acts. They are chosen out of the world by that call whereby God fulfills what He has predestined: whom He did predestinate, them He also called. (Rom. 8:30)