The burden… [Jesus] wants to take from us is the burden of religion. It is the yoke of the law, imposed on the people of His time by the religious teachers, the wise and understanding, as He calls them in our words, the Scribes and Pharisees, as they are called usually. Those who labor and are heavy laden are those who are sighing under the yoke of the religious law. And He will give them the power to overcome religion and law; the yoke He gives them is a “new being” above religion. The thing they will learn from him is the victory over the law of the wise and the understanding, and the law of the Scribes and Pharisees.
How does this concern us? Why does this concern all men, in all situations? It concerns us because, with all human beings, we are sighing under the law, under a law which is religion and a religion which is law. This is the depth of the word of Jesus; this is the truth, implied in the emotional power of His words. Man labors and toils, because he is that being which knows about his finitude, about his transitoriness, about the danger of living, and about the tragic character of existence. Fear and anxiety are the heritage of all people, as Paul knew when he looked at the Jews and the Pagans. Restlessness drives man during his whole life, as Augustine knew A hidden element of despair is in every man’s soul, as the great Danish Protestant, Kierkegaard, discovered. There is no religious genius, no keen observer of the abyss of the human soul, nobody capable of listening to the sounds of his heart, who would not witness to this insight into human nature and human existence. Splits and gaps are in every soul: for instance, we know that we are more than dust; and yet we know also that we are going to be dust. We know that we belong to a higher order than that of our animal needs and desires; and yet we know that we shall abuse the higher order in the service of our lower nature. We know that we are only small members of the spiritual world; and yet we know that we shall aspire to the whole, making ourselves the center of the world.
This is man; and because this is man, there is religion and law. The law of religion is the great attempt of man to overcome his anxiety and restlessness and despair, to close the gap within himself, and to reach immortality, spirituality and perfection. So he labors and toils under the religious law in thought and in act….
We are all permanently in danger of abusing Jesus by stating that He is the founder of a new religion, and the bringer of another, more refined, and more enslaving law. And so we see in all Christian Churches the toiling and laboring of people who are called Christians, serious Christians, under innumerable laws which they cannot fulfill, from which they flee, to which they return, or which they replace by other laws. This is the yoke from which Jesus wants to liberate us. He is more than a priest or a prophet or a religious genius. These all subject us to religion. He frees us from religion. They all make new religious laws; He overcomes the religious law.
–Paul Tillich, The Shaking of the Foundations, Chapter 11, which you may read there.