Matthew Poole and continuators on Romans 9:15

15. For he saith to Moses, I will have mercy on whom I will have mercy, and I will have compassion on whom I will have compassion .

q. d. God is not chargeable with any injustice in Electing some, and not others; for this is an Act of meer mercy and compassion, and that can be no violation of Justice. To prove this, he cites a Testimony out of Exod. 33.19. vid. locum. There He tells Moses, That the good Pleasure of His Will, was the only Rule of all his favourable and merciful Dealings with the Children of Men. The same thing is intended and expressed in Two several Phrases: And the Ingemination imports the Freeness of God's Mercy; nothing moves Him thereunto, but his own gracious Inclination; and also the Arbitrariness thereof; it depends only upon his good Will and Pleasure. The Sum is, if God shew Mercy to some, and not to others, He cannot be accused of injustice, because He injures none; nor is He obliged or indebted to any.