Reformed Covenanter
Cancelled Commissioner
I did not want to put this one in the Calvinism forum, as the author was a Lutheran. 
Still, I have seen him cited by a fair few Reformed authors in my time. His comments on prayer and divine foreordination are of great practical help:
... Neither let us abuse that most sweet sentence of the ready good-will of God toward us, which ought rather to be an incitation and a motive to excite and confirm our diligence & confidence in prayer. There be some which reason thus, or at least do trouble themselves with those conceits: seeing God unasked, and before we pray doth know, yea beforehand hath set down & appointed what he will do and what he will give: we do therefore either ask in vain, that which otherwise should come to pass; or else do wickedly in praying, as though we hoped by our prayer to turn God from his firm decree and purpose, and so make him changeable and constant [inconstant?].
To this objection some answer thus. If that which we ask be ordained beforehand to be done, then we pray upon good and sure confidence. If it be not, yet we go not about to hinder or stop the course of God’s predestination; because we pray that God’s will may be done. But Luther’s exposition is more plain & safe; to wit, that we are not commanded to busy our selves about the hidden foreknowledge of God, or to search into his secret counsels: but we must dispose our selves according to his will revealed unto us in his word, where he teacheth that by repentance and prayer, God’s wrath is appeased, many dangers and evils are avoided, and many benefits obtained. Jer. 18. v. 8. Ezek. 33. v. 11.1. King. 8. v. 56. And therefore he hath straitly charged us to pray: yea he is angry when no man sets himself by prayer between the Lord and the land lest it be destroyed, Ezek. 22. v. 30. Both these therefore do warn us to pray, first that God of his own accord is ready to help, and knoweth what we want, & what himself will do. ...
For more, see Martin Chemnitz on prayer and divine foreordination.
Still, I have seen him cited by a fair few Reformed authors in my time. His comments on prayer and divine foreordination are of great practical help:... Neither let us abuse that most sweet sentence of the ready good-will of God toward us, which ought rather to be an incitation and a motive to excite and confirm our diligence & confidence in prayer. There be some which reason thus, or at least do trouble themselves with those conceits: seeing God unasked, and before we pray doth know, yea beforehand hath set down & appointed what he will do and what he will give: we do therefore either ask in vain, that which otherwise should come to pass; or else do wickedly in praying, as though we hoped by our prayer to turn God from his firm decree and purpose, and so make him changeable and constant [inconstant?].
To this objection some answer thus. If that which we ask be ordained beforehand to be done, then we pray upon good and sure confidence. If it be not, yet we go not about to hinder or stop the course of God’s predestination; because we pray that God’s will may be done. But Luther’s exposition is more plain & safe; to wit, that we are not commanded to busy our selves about the hidden foreknowledge of God, or to search into his secret counsels: but we must dispose our selves according to his will revealed unto us in his word, where he teacheth that by repentance and prayer, God’s wrath is appeased, many dangers and evils are avoided, and many benefits obtained. Jer. 18. v. 8. Ezek. 33. v. 11.1. King. 8. v. 56. And therefore he hath straitly charged us to pray: yea he is angry when no man sets himself by prayer between the Lord and the land lest it be destroyed, Ezek. 22. v. 30. Both these therefore do warn us to pray, first that God of his own accord is ready to help, and knoweth what we want, & what himself will do. ...
For more, see Martin Chemnitz on prayer and divine foreordination.
