Not a single one of all the good promises the Lord had given to the family of Israel was left unfulfilled; everything he had spoken came true. Joshua 21:45 (New Living Translation, NLT)

God promised the land to the forefathers and to their descendants. We see that not one of the Lord’s promises failed. God promised them the land and it was theirs for the taking.

God fulfilled the promise to give them the land. The book of Joshua shows the conquest complete (Joshua 10:40-42) yet incomplete (Joshua 23:5). How can it be both? Because God promised it to them but they had to go in and possess. It didn’t just drop in their lap.

Let me give a practical and simple example. Let’s say that I hold out my hand and say, “Here are the keys to my car- I offer it to you.” Have I given you the keys? Yes, I have. But you do not have possession of the car until you take action and take the keys.

For all the promises of God in him are yea, and in him Amen, unto the glory of God by us. II Corinthians 1:20 (KJV) emphasis mine.

Of God means that God has done His part. By us refers to the fact that we have a part to play. We must cooperate with God. As we do, we will have all that God promised.