Musculus (by way of Marlorate):

“I praye for them, I praye not for the world: but for them which thou haste giuen mee, for they are thine.”

…[Calvin] So that he plainly affirms that he prays not for the world: because he cared for his own flock only, which he had received of his Father’s hand, notwithstanding this might seem very absurd.

For there cannot be a better Rule of prayer devised, then if we follow Christ our Captain and master. But we are commanded to pray for all men, yea even for our enemies [Math. 5.4., 1. Tim. 2.1., Luk. 13.34.]. C. [Calvin] Furthermore Christ himself prayed after this Indifferently for all men saying, “Father forgive them: for they [know not] wotte not what they do.”

[Musculus] Moreover it is the office of a Mediator not only to pray but also to offer. And he offered himself upon the Cross for all men. For (as says Paul) “Christ died for all men.” Finally Saint John says that he is the “propitiation for the sins of the whole world.” How then says he that he prays not for the world seeing he died for all men, and was the propitiation for the sins of the whole world? C. [Calvin] this may be briefly answered, that these prayers which seem to be made for all men are notwithstanding restrained to the elect of God.

We ought to wish this and that man be saved and so to comprehend all mankind because yet we cannot distinguish the elect from the Reprobate yet notwithstanding we pray withal for the coming of God’s kingdom, wishing that he would destroy his enemies.

This is even as much as to pray for the salvation of all men whom we know to be created after the Image of GOD, and which are of the same nature we are of, and do leave their destruction to Judgment of GOD whom he knows to be reprobate. There was another certain special cause of this prayer, which ought not to be drawn into example. For Christ’s prayer proceeded not only from the bare sense of faith and love, but also from the feeling of his Father’s secret Judgments which are hidden from us, so long as we walk through faith.

M. [Musculus] Therefore because we know not who they are which so appertain unto the world that they can never be drawn away from the same, it is meet that we wish well unto all men, and to declare our good-will by prayer. C. [Calvin] Furthermore by these words we gather, that they whom it pleases, God to love out of this world shall be heirs of eternal life: and that this difference depended no upon man’s merits but upon the mere good-will and grace of God.

For the which place the cause of election in men must first begin with faith.

Christ plainly pronounces that they were the Father’s which were given unto him.

Augustine Marlorate, A Catholike and Ecclesiasticall exposition of the holy Gospel after S. Iohn, trans., Thomas Timme (Imprinted at London by Thomas Marshe, Anno Domini, 1575), John 17:9; pp., 560-561. [Pagination irregular; stated pagination cited here; and underlining mine.]