My own opinion: In the past 130 years, the Teaching Church has focused strongly on moral doctrine as applied to social justice. From Pope Leo XIII’s 1891 encyclical, Rerum Novarum, to Pius XI’s Quadragesimo Anno, to John XXIII’s Mater et Magistra, and so many more, the Teaching Church has expounded on needful moral doctrine related to the social climate in our historical era, called the Industrial Age. The focus on these teachings is related to human labor, the rights and dignities of humans who do work. Catholic teachings on this subject do not fit well into modern political tribes; as we would expect, Christ’s teaching on the subject transcends human banality. The most basic and powerful teaching of Jesus on this subject was not by words, but by His deeds.
2 And on the sabbath he began to teach in the synagogue; and many who heard him were astonished, saying, "Where did this man get all this? What is the wisdom given to him? What mighty works are wrought by his hands! 3 Is not this the carpenter, the son of Mary? (Mk 6:2-3a)
Jesus was a carpenter.
Matthew describes this scene with one difference:
54 And coming to his own country he taught them in their synagogue, so that they were astonished, and said, "Where did this man get this wisdom and these mighty works? 55 Is not this the carpenter's son? Is not his mother called Mary? (Mt 13:54-55)
Jesus’ father, Joseph, was also a carpenter. Jesus grew up in a carpenter’s home and continued the family trade.
Furthermore, we know that Jesus began His ministry when He was about 30 years old. We also know that at the age of 12, He was teaching learned rabbis in the Temple (Lk 2:46-49), so He was certainly capable to begin His ministry from at least the age of twelve. But He didn’t; he spent eighteen years being a carpenter. Then he spent three years in His ministry. The Redeemer spent most of His life, most of His time in this world as a workman, not a teacher. Why? Because labor is a very important element in our spiritual lives and has a critical redemptive value.
Let’s go back that primal scene of The Fall. The first Adam received a harsh rebuke from his Father:>/p>
17 And to Adam he [the Lord God] said, "Because you have listened to the voice of your wife, and have eaten of the tree of which I commanded you, 'You shall not eat of it,' cursed is the ground because of you; in toil you shall eat of it all the days of your life; 18 thorns and thistles it shall bring forth to you; and you shall eat the plants of the field. 19 In the sweat of your face you shall eat bread till you return to the ground, for out of it you were taken; you are dust, and to dust you shall return." (Gn 3:17-19)
The ground became cursed – Adam would have to toil to eat; in the end he will die – return to that same cursed ground. Life will consist of work and death. This is, indeed, a curse. (NB: The name “Adam” is a variation on the Hebrew word for ground: Adamah. The curse of the ground is also a curse of Adam.)
Our Redeemer is the second Adam. Where the first failed and received curses, curses to befall his progeny, the second Adam succeeded and received blessings, blessings for His progeny, His Mystical Body. All Christians are well aware that we receive eternal life through Jesus – the curse of death has been lifted. But hardly any Christian remembers the other part of the curse, that of harsh labor. Our Redeemer should have resolved that also. And He did. Just as we still die, but our death opens us to the Divine Life, so we still must work, but our work now has a redemptive characteristic.
How is labor redemptive? It was originally to be a participation in God’s work of creation. He made the world, then He told our first parents:
28 And God blessed them, and God said to them, "Be fruitful and multiply, and fill the earth and subdue it; and have dominion over the fish of the sea and over the birds of the air and over every living thing that moves upon the earth." (Gn 1:28)
God made the earth, but humanity was to “subdue it.” This was God’s plan from the beginning, before the Fall: to give us a part in His creative act. What He started, we were to finish. What He planted, we were to harvest. After the Fall, God cursed the ground so that it would require toil to get food from it, toil being the tedious exertion of our energy and all for a little food. This is not subduing the earth; this is being subdued by the earth. The historical result is famous and terrible: countless human beings who lived and died for nothing more than to labor, often the fruits of their labor taken by the more powerful. Slavery. Servitude. Disparity of wealth and power. Endless poverty for so many souls. The value of human labor was practically nil, and so the value of a human was nothing.
Those who unite themselves to Christ’s Mystical Body enjoy a new dimension in their labor: they do it for God and in union with God.
Work honors the Creator's gifts and the talents received from him. It can also be redemptive. By enduring the hardship of work in union with Jesus, the carpenter of Nazareth and the one crucified on Calvary, man collaborates in a certain fashion with the Son of God in his redemptive work. He shows himself to be a disciple of Christ by carrying the cross, daily, in the work he is called to accomplish.212 Work can be a means of sanctification and a way of animating earthly realities with the Spirit of Christ. (CCC 2427)
When He was baptized, Jesus sanctified the waters so that we can receive grace in baptism. When Jesus suffered during His passion, He sanctified suffering so that all who suffer can participate in the Redemption. When Jesus did anything, He sanctified the thing, so that we can enjoy and participate in His life. So when Jesus spent the better part of His life in labor, we can now participate in His Redemptive life when we work. Our work is no longer mere toil; it is sanctification which is the highest good we can achieve, no one can take it from us, and it advances our dignity rather than reduces us to subjugation. This is what we mean by the rehabilitation of work. Jesus restored the original plan to subdue the earth, however it has now been elevated from participation in the Creation to participation in the Redemption.
FOOTNOTE: That so many popes have taught on this subject during our age implies we should be especially aware of our moral obligations in its regard. The political solutions offered by modern political parties are all a mix of right and wrong; they ignore the spiritual dimension of our nature. The above link to the Catechism of the Catholic Church (CCC) is a quick start to understanding the morality of human labor. I also recommend, if you can find the time, the above links to the three foundational encyclicals on this subject. Good reading!