The law of the old covenant was compared to a yoke (Sir 6:25). The yoke was heavy. It comprised 612 commandments. Every one of these commandments had to be obeyed, or the offender would be punished — sometimes with capital punishment. "Whoever falls into sin on one point of the law, even though he keeps the entire remainder, has become guilty on all counts" (Jas 2:10). Because of the nature of the law and because of our fallen human nature, "all who depend on observance of the law...are under a curse" (Gal 3:10).
Jesus promised rest to those wearied and burdened from living under the law (Mt 11:28). He gives us another yoke, which is easy and light (Mt 11:29-30). However, this does not mean that He abolished the law (Mt 5:17). He promised: "Until heaven and earth pass away, not the smallest letter of the law, not the smallest part of a letter, shall be done away with until it all comes true" (Mt 5:18). Jesus fulfills the law (Mt 5:17). He has much higher standards than the old law on relationships, sexual morality, marriage, speech, justice, and love (Mt 5:20-47). Jesus added hundreds of stricter commandments to the 612 burdensome laws of the old covenant. Jesus commands: "You must be made perfect as your heavenly Father is perfect" (Mt 5:48). Jesus sets the highest standards ever set.
How can Jesus' super-heavy yoke be easy and light? It is light because He does not expect us to observe the law and carry His yoke by our willpower but by His grace. Do the impossible. By Jesus' grace, take Jesus' yoke on your shoulders.