Another wonderful thing we can learn from Johan Gerhard is a little patristics. It can be intimidating to look at the NPNF series: where to begin? Gerhard peppers his discussions of specific theological topics with quotations from the Fathers. By noting the titles he quotes from again and again you can be directed to the truly important works. Here's one from today's bit of editing of Gerhard's article on Free Will and Free Choice:

[Chrysostom] (Homily 30, on Acts): “Let us think that nothing is our own. In fact, even faith itself is not our own work. That is not ours but God’s. Hear the apostle as he says: ‘Even this is not of yourselves., it is the gift of God.’”