Let's first consider that nowhere is the youngest son called "prodigal". Basically, the word means that he was a carefree spender on lavish things. Was spending really his problem, though?
In verse 13 it is said that he "wasted his substance on riotous living." Substance is what he had, but what he left with was provided by his father. It would appear that his father was prosperous because he had an estate to settle and gave the younger son his portion, verse 12. Not only did the younger son get his portion, but the older did as well! This was a fair deal and no one had a right to complain. Both brothers took from the father their portion. The only reason either had an inheritance was because they each were heirs to the father.
The father was generous and because of their relationship, he gave generously to both. Nowhere does it say that either DESERVED anything, but they received because of the father's love for them. These undeserved gifts are what is called "grace".
Was "lavish spending" the younger son's problem? That is what being prodigal suggests. "Riotous" was how they younger son chose to live. Another adjective for that is "dissolutely" from the Greek asotos, meaning "unrestrained" living. As such he did "what was right in his own eyes", as people have always done (Deuteronomy 12:8)! Therefore being prodigal wasn't the big issue, it was "doing what he wanted to do without regard to God's will." His lifestyle was the same as even the worst Satanists whose credo is "Do what thou Wilt."
The younger son was worse than prodigal. He was in rebellion to God. Of course this parable was addressed to publicans, sinners, Pharisees and scribes, but all heard him, even his disciples!
Publicans were tax collectors and as such were rogues. Their wages were not taxes, but over-taxing people to enrich themselves. Sinners were any who lived sinful lives, and could have been even some of the disciples who had yet to be new persons. The Pharisees were the hypocrites who always plotted to catch Jesus speaking against the Law, and the scribes were the lawyers, not only in civil matters, but condemning whoever broke the religious Law. The latter two groups were what I will call "technically religious, but practically unrighteous" because their religion was not one of love, but works.
Works are not a bad thing! We know from the Apostle John that for those who are born again, obedience is a demonstration of love for God, but for those who do not love God, obedience is as filthy rags (Isaiah 64:6). Hence, everyone within hearing should consider Jesus' words.
"There is nothing new under the sun," which is a saying of Solomon. Hence, have others done what the prodigal son did before him? I submit that we all have and the first prodigal son was Adam himself. "But, how can that be, you ask, for there was no older son?" My contention is that within each of us, since we are under the law of God and the law of the flesh, are both the younger and older sons. In other words, the younger and older sons are patterns of which each of us or composites! The older son works under the law of the flesh, and the younger, the law of the Spirit, even though that the younger son wars between the flesh and Spirit.
Our model is Adam; he had the same composition as we do. Within him were both sons. One was of the flesh and the other of the Spirit. Originally, in complete innocence, the Father's heir was obedient out of love. There were two sons, the older being the Word and the younger being Adam.
The Word was NOT however, symbolic of the older son in the parable. He was Jesus who was speaking. There is no parallel with the older son!
If the flesh is examined there were two spiritual sons. Let's examine that premise.
God had provided all the needs of Adam, and Eve for that matter. All their substance, or sustenance, was provided. They could eat of any tree in the Garden, but one, but even though his Father supplied him well, Adam was tempted to want more just as the prodigal son desired three things: wealth, pleasure, and independence. The independence part was "living as he wilt."
When Adam ate of the tree what was offered thereon?
Genesis 3:6 "And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat."Epicurean food, beauty, and wisdom. These describe wealth, pleasure and independence, because self-wisdom is independence from God. The prodigal son was another Adam. He sought what Adam sought! God had already given Adam food, beauty things and intelligence, but Adam wanted his own will to do what he wanted. When he ate of the fruit of the tree, he got his portion and left God from a spiritual standpoint.
"Where was the older son?" you ask. He was the lost Adam. He was created by disobedience. When Adam rebelled, the younger son was still there, but there emerged another creation, the old son, representative of the old creature, but like Jesus, the younger son preceded the older and was the legitimate heir! The younger Adam was like Isaac, the older the Esaw.
And when did the old creature, the older son emerge?
Genesis 3:7 "And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons."Why was Adam now the older son? Because he tried to save himself from death. How so? To cover his own sin, he (and Eve both) made aprons to cover their shame. They were doing things to save themselves from God's wrath. Right that instant in time two other gods besides God were created. These false gods believed that they had the power by works to save themselves. Ever since, we each are these gods. The older brother was the old creation, Adam, another god besides God!
Both brothers were there in the flesh. Internally, there was the older brother who was technically religious, but along with him was the younger brother who loved his father. As such, God the Father saved the younger persona.
Because they were ashamed and sorrowful God did this:
Genesis 3:21 "Unto Adam also and to his wife did the Lord God make coats of skins, and clothed them."God covered them with the skin of animals who died in their place. For the first time ever blood was shed by God for mankind. God saved them as they were unable to save themselves by their own hands! Adam, the younger son, came back to the Father. The older son was still there because sinful Adam represented the old creature, whereas ashamed Adam represents the persona of Adam called the new creation!
Each were of the flesh, but one came home out of shame. The other stayed home out of his own works. Each of us have both the younger and the older son within us just as Adam did. We want to save our little gods by our own works, but it takes Jesus to save. Jesus was the Father figure in the parable and he is the same Father in the Adam story.
Well, the prodigal son came home to fanfare. Guess what? Adam did as well. All the angels sang when Adam became a new person, as they surely did for the younger son, because all the angels celebrate when even one soul is saved. Inside the old person wants to work for salvation and is upset because that doesn't impress the Father, while the new person, the younger son, just accepts the mercy of the Father as a free gift. That is grace and grace has set us free... me as the new creation, and the prodigal, as the younger son.
It's important to understand that Jesus speaks to everyone when he speaks because we all have sinned, even the apostles! I bet that each one of the disciples identified with both the younger and older sons for those who were Christians. For those who were not, it would have been the older son, but surely they were taken back by the humility of the younger!