What is a decree?

In Chapter 2 we are introduced to various forms of the word of God.

One of these is described as God's decrees which are "a word of God which causes something to happen" and this is applied particularly to the act of creation (initial and ongoing).

I don't think that this covers completely the scope of God's decrees - see for example:

Exodus 15:25,26 - 'There the LORD made a decree and a law for them, and there he tested them. He said, "If you listen carefully to the voice of the LORD your God and do what is right in his eyes, if you pay attention to his commands and keep all his decrees, I will not bring on you any of the diseases I brought on the Egyptians, for I am the LORD, who heals you."'

1 Chronicles 16:17,18 - 'He confirmed it to Jacob as a decree,to Israel as an everlasting covenant: "To you I will give the land of Canaan as the portion you will inherit."'

Romans 1:32 - 'Although they know God’s righteous decree that those who do such things deserve death, they not only continue to do these very things but also approve of those who practice them.'