This is the post #14 of the Calvin's Institutes summary series.
We are created beings. To speculate about what God was doing before the creation or to suggest a "better" way to create the world than the way God did is to go beyond what the Creator revealed to us. It is useless, dangerous, and dishonouring to God who spoke to us about the creation. Humility is paramount.
The six days of creation accounted in Genesis shows us God's special and great care and love towards human beings.
God rules over all things. Any evil beings are the corruption of what God created.
Angels are real spiritual beings that protect and assist believers at the command of God. God does not need them to protect and guard us, but they are made and given such service so we may be comforted in our weaknesses. However, we must guard our own minds against such sins as to worship the angels or to take even a slightest degree of glory from God and assign to them. Also we must be careful not to speculate beyond what the Scripture teaches us. Hence, for example, a personal guardian angels are useless and dangerous speculations.
Demons, devils, and Satan are real and powerful spiritual beings. They are corrupt angels, who are still under God's sovereign rule. They want to usurp God's Kingdom and lead people to hell, and they do attempt many things to achieve that, but they are all under God's complete control. Hence, the believers are not to fear them, yet, be vigilant in asking God for protection and help in fighting against them at the same time.
All things are made by God, and they show His great power and they are ruled by God to work for our good and salvation so we may love and praise God.