Abraham gave his only begotten son before God physically manifested the giving of His only begotten son to the world. We can never out give God!
Even when the rain destroyed the world o Noah, the water from under the earth was released before the one from heaven began to rain!
The unwritten code is that you release what you have before what you don't have can be given to you!
The Woman of Zarephat released the water and the flower she had fro her and child to eat before they die before Elijah released the abundance of heaven to sustain them till the rain came in Isreal!
A stingy life can never get anything new because God can not trust him.