Why did the father not reward the older brother for his long years of diligent service? The answer to that question contains one of the most important truths you will read in this book: it was impossible for the father to reward the son with that which already belonged to him by inheritance! All the skinny goats and fatted calves already belonged to the older son, for when the father gave the younger son his inheritance, the older son had received his also: “So he divided to them his livelihood” (Luke 15:12). Every single calf and goat already belonged to him! He could have had a party every day of his life.
The father said to him: “All that I have is yours” (Luke 15:31). What a tragedy! Since the older brother perceived himself as a servant rather than a son, he awaited a reward and forfeited the enjoyment of his inheritance. Everything his father had was his by inheritance, but he was never able to receive what was rightfully his to enjoy. His servant mentality limited him to the anticipation of a wage or reward and kept him from recognizing his liberty as an heir to appropriate what was his. Why do Christians who earnestly desire everything that God has for them never receive the blessings promised to them? The answer is clear: they await a reward for their service, and, because they are heirs, the Father can never give them as a birthright.
The Birthright, 2010, Zondervan, 45-6