Yeshua is coming back. Yeshua is Jewish. When He returns, it will be according to the Biblical calendar, not according to the calendar of this world or any man-made dates of religious observances for significant events or holidays. God is not a God of coincidence but of precision. God's appointed times are everlasting ordinances for all generations. He established His calendar and reveals Himself to us through it. Changing the times is a deliberate scheme of those opposed to God. (Consider Daniel 7:25.) Moreover, Yeshua rebuked those who did not have discernment of their times. (See Luke 12:54-56.) Therefore, we seek to stay in step with God and His times through Biblical understanding.
Not Law. Not Tradition. Under the New Covenant, we are not subject to the legal requirements for observing the Feasts of the Lord or the Biblical months because the requirements of the Law were fulfilled for us in Messiah. As such, followers of Messiah today can observe these Feasts or not however the Lord leads them. (See Galatians 4:10; Colossians 2:16.) Unfortunately through the centuries, the dates and customs of Christian holidays have badly strayed and been cut off from their Biblical foundation. At the same time, the Jewish traditions and calendar have also gone amiss in their Biblical accuracy. Therefore, instead of legalism or tradition, we look to the Word of God for what He reveals through Scripture about His appointed times and their Biblical meaning and significance.
Biblical Feasts are a shadow of Messiah. Yeshua observed the Feasts of the Lord out of His own perfect obedience to the Law of God. He also looked forward to the ultimate fulfillment of the Feasts through His life, death, resurrection, and return to usher in the age to come. Each of the Biblical Feasts reveal certain aspects of who Yeshua is, what He accomplished for us, and what will come to pass upon His return. They were originally designed by God to keep Israel focused on Him, to help them remember all He has done for them, and to train them in true and proper worship. They can do the same for us if we take note of them in our lives today. In fact, Messiah instructed His disciples to always be alert and discerning of the times. Walking with God through His calendar each year is one way of doing this.