He can do nothing which is contradictory to His nature. He cannot lie. He cannot tempt. He cannot be unjust. It has always been an enigma to me that Calvinists say God has directed his chosen to go to a group of people and lie to them...ie....to say If you believe in the finished work of Jesus Christ on the cross, His death, burial, and ressurection, that you will be saved,...knowing Calvinism teaches that they, if not the elect, will never, can never be save. Why would God order us, “Thou shalt no lie.” and then tell Calvinists to lie to those reprobated unto damnation, for all eternity, for His good pleasure...I think that is the statement of the Pope of Genieva.
Of course, that's not what Calvinists say at all. Calvinists believe the Gospel call should be preached to all men, confident that those to whom God gives new ears and new eyes and a renewed mind and a rebirth, all by the Holy Spirit, will at a time of God's choosing, believe in Jesus Christ as Lord and Savior.
Calvinists believe in the Biblical truth that unless a man is born again by the Holy Spirit, that man will not want to believe.
And a man's rebirth by the Holy Spirit is not man's decision, but God's decision, ordained to occur from before the foundation of the world when God's plan of creation in all its scope and detail was purposed by God for His glory. Every jot and tittle. Every hair numbered. Every star named.
"According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love: Having predestinated us unto the adoption of children by Jesus Christ to himself, according to the good pleasure of his will, To the praise of the glory of his grace, wherein he hath made us accepted in the beloved." -- Ephesians 1:4-6
"And he said, Therefore said I unto you, that no man can come unto me, except it were given unto him of my Father." -- John 6:65 "So then it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy." -- Romans 9:16
Obviously all men do not receive saving grace or else all men would be saved. God's grace accomplishes that which God ordains. It is not a slight thing, God's grace. It is the enlivening spirit of all that exists. Saving grace is Christ paying for a man's sins so that he then stands blameless before God because the Lamb slain from the foundation of the world has taken on the punishment rightly due him, all through nothing in himself; through God's unmerited mercy alone.
Calvinism simply 1) states the obvious; and 2) gives all the glory to God alone, from beginning to end.