God left us His will so we would know what to do with His property. But what is God's property? The answer is...everything! God created the heavens and the earth, He created the land and all the animals that have ever existed. God also created us. Everything that exists belongs to God because He created it. God put mankind in charge of taking care of the land and the animals. He also charged us with taking care of each other.
The Old and New Testaments are also covenants God made with us. A covenant is an agreement between to parties -- in this case between God and humans. The agreement includes a promise made by both sides to fulfill the agreement. The Bible is full of God's promises. The overarching promise is that God grants salvation to anyone who is faithful to Him.
God promises many great things and He fulfills every promise. "Not one word has failed of all the wonderful promises he gave" (1 Kings 8:56). God fulfilled His promises then and He still does today. Have faith and trust that God will come through on His promise and will always love and protect you.