Q: What special act of providence did God exercise toward man in the estate wherein he was created?
A: When God had created man, he entered into a covenant of life with him, upon condition of perfect obedience; forbidding him to eat of the tree of the knowledge of good and evil, upon the pain of death.

Compare Genesis 2:17. And the Lord God commanded the man, saying, Of every tree of the garden thou mayest freely eat: But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.
With Romans 5:12-14. Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned: (for until the law sin was in the world: but sin is not imputed when there is no law. Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.
Romans 10:5. For Moses describeth the righteousness which is of the law, That the man which doeth those things shall live by them.
Luke 10:25-28. And, behold, a certain lawyer stood up, and tempted him, saying, Master, what shall I do to inherit eternal life? He said unto him, What is written in the law? how readest thou? And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself. And he said unto him, Thou hast answered right: this do, and thou shalt live. And with the covenants made with Noah and Abraham.
Genesis 2:17. But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die.

Westminster Project - See Thomas Vincent's Scriptural explanation of the WSC