Any kind of law-keeping is burdensome and amounts to a “heavy yoke” of oppression because
no amount of law-keeping can bridge the gap between our sinfulness and God’s holiness.
WE CANNOT PERFORM OUR WAY TO THE PEARLY GATES!
What makes Jesus’ yoke easy and his burden light is that in Jesus’ own active obedience (i.e., his perfect fulfillment of the Law of God), He carried the burden that we were meant to carry. His perfect obedience is applied (imputed) to us through faith, just as His righteousness was exchanged for our sin at the cross. Our obedience to Jesus then becomes our “spiritual worship”.
Furthermore, we are indwelt by the Holy Spirit who works in our lives to mold us into the image of Christ, thereby making the yoke of Jesus easy and His burden light. The life lived by faith is a much lighter yoke and a much easier burden to carry than the heavy and burdensome yoke of self-righteousness under which we continually strive to make ourselves acceptable to God through works.