In this Lord's word Bible study, the Prodigal Son, I have explained the meaning using two other documents, 1) Famine/Hunger, and 2) The Lost Sheep, but I will also give you some additional help in understanding this parable.
All text taken from the King James Version of the Bible
There are two story lines running in this parable at the same time, and you will have to keep both story lines in your mine at the same time in order to understand this parable. It is about his (biological) father, and his (heavenly) Father, as we will see once we get into the story.
The parable or the story of the Prodigal Son is about two sons, and the younger son asks his (biological) father for his inheritance. Shortly after receiving his inheritance, the younger son gathers his things and leaves home and goes away, or goes into "a far country," to squander or waste his inheritance (money) on fancy (or, riotous) living, eg., parties, clothes, etc. - in other words, living the so-called "good life," and during this time, forgot about God. Now that is very important in understanding this story so I will repeat it - during the time the younger son was away living a riotous life, he forgot about God.
Goes into "a far country" - means no longer following God and the ways of God
Now when his inheritance (money) ran out, a famine hits the country or the land where he was living and he had no money to buy food or clothing and so he went and joined himself to a citizen (it means, he went to work for a man of that country) and the man sent him into the fields to feed the swine (pigs). At that time, in that country, feeding the swine, or pigs, is the lowest job you can be given to do. And he would have desired to eat the same food that the swine ate - the husks - but nobody would give him any food. - See - Famine/Hunger
Remember: Not only is this story talking about the physical hunger, but also the spiritual hunger, or famine.
Then he started thinking and said to himself, Luke 15:17-18 - ...How many hired servants of my father's have bread enough and to spare, and I perish with hunger! (18) I will arise and go to my father, and will say unto him, Father, I have sinned against heaven, and before thee. - See - Meat of God or Bread of Life
Now I want to point out a few things here for you. First of all, we know that the young man has moved away from his family to do his own thing and now he wants to come back home, and secondly, the word "Father," is written with a capital "F," so we know this is referring to our heavenly Father - God, it goes on to say, ...I have sinned against heaven, and before thee, (his biological father). So he has sinned against his heavenly Father, as well as his biological father.
Let us look at -
Lam.3:40 - Let us search and try our ways, and turn again to the LORD.
Luke 18:13-14 - And the publican, standing afar off, would not lift up so much as [his] eyes unto heaven, but smote upon his breast, saying, God be merciful to me a sinner.
This is one of the most important points of this parable or story and what I want you to see is that this young man did what he wanted and did not lead a Godly life, but realized his mistake, repented and asked not only his (biological) father's forgiveness, but what is more important, realized he had sinned against his heavenly Father - God, and asked for his forgiveness.
Now let us continue -
Luke 15:19 - And am no more worthy to be called thy son: make me as one of thy hired servants.
Here the son is asking his (biological) father to let him come home and because he feels he has dishonoured his father (dad), by not leading a Godly life and spending all of his inheritance (money) - he asks his father (dad) to let him work in the field as one of his hired servants - so he can have food to eat - see verse 17 again. He also feels that he is not worthy to be called a son, neither does he feel he is worthy of being a son of God. - See - Heir and Joint-Heir With Christ
Luke 15:20-21 - And he arose, and came to his father. But when he was yet a great way off, his father saw him, and had compassion, and ran, and fell on his neck and kissed him. (21) And the son said unto him, Father, I have sinned against heaven, and in thy sight, and am no more worthy to be called thy son.
Again, we have the two story lines going at the same time, one is the son is asking forgiveness of his (biological) father, but more importantly his (heavenly) Father, let me again refer to other scripture.
Ps.51:1-4 - Have mercy upon me, O God, according to thy lovingkindness: according unto the multitude of thy tender mercies blot out my transgressions. (2) Wash me throughtly from mine iniquity, and cleanse me from my sin. (3) For I acknowledge my transgresions: and my sin [is] ever before me. (4) Against thee, thee only have I sinned, and done [this] evil in thy sight: that thou mightest be justified when thou speakest, [and] be clear when thou judgest.
Now the (biological) father is extremely pleased that his son has decided to return and says to his servants to put the best robe on him, a ring on his hand and shoes on his feet, and to bring a fatted calf and kill it so they can eat and celebrate his son coming back to him (or, to the fold).
Likewise, our heavenly Father is also pleased when one of his children who has been lost - that is, doing there own thing and not following the ways of God - returns to him.
Luke 15:24 - For this my son was dead, (spiritually) and is alive again: he was lost, (spiritually), and is found. And they began to be merry.
Now the older son returns from the field, and as he gets closer to home, he can hear and see the celebration of music and dancing, and he asked one of the servants what this celebration was all about, and the servant tells him that his brother has returned and his father (dad) is very happy because he has come back.
Well this makes the eldest son angry and jealous and he would not attend the celebration, so his father (dad) comes to him and talks with him. The older son says to his father (dad), I have served you all these years and I have never transgressed (or, broken) any of thy commandments and you have never given me a kid (a goat) that I might kill and have a celebration with my friends, but as soon as your younger son comes back home from having squandered his inheritance with harlots, you kill the fatted calf for him.
Let me show you the meaning of -
yet thou never gavest me a kid, that I might make merry with my friends - Luke 15:29
Matt.20:10-12 - But when the first came, they supposed that they should have received more; and they likewise received every man a penny. (11) And when they had received [it] they murmured againist the goodman of the house, (12) Saying, These last have wrought (or, laboured/worked) [but] one hour, and thou hast made them equal unto us, which have borne the burden and the heat of the day. - See - Parable of the Workers in the Vineyard
Let us continue with -
Luke 15:31-32 - And he (the dad) said unto him, Son, thou art ever with me, and all that I have is thine. (32) It was meet that we should make merry, and be glad: for this thy brother was dead and is alive again; was lost and is found again. - See - The Lost Sheep
In the above scripture, verse 31 - not only is this referring to the father (dad) and the oldest son, but it is also referring to God speaking with his Son (Jesus) - ...thou art ever with me, all that I have is thine, - it is also Jesus speaking with us, if we do not stray. In verse 32 - the son, or brother that left home and went into "a far country," was dead, "spiritually," and is alive again; was lost "spiritually," and is found again - he repented, or has "come home" from the far country and asked for forgiveness not only from his biological father, but from his heavenly Father also - and both have received him with open arms.
This document is meant to help you to understand your Bible more easily, however, you will need to study and read your Bible more, as well as other biblical documents. Let no one deceive you, because you are responsible for your own salvation.