Numbers 29:39 These things ye shall do unto the Lord in your set feasts, beside your vows, and your free will offerings, for your burnt offerings, and for tpyour meat offerings, and for your drink offerings, and for your peace offerings.
The Fall of the year was to be a special season of Feasts and celebrations, in the seventh month (Sept-Oct): New Year, Day of Atonement, Feast of Tabernacles. There were to be many offerings and sacrifices during this period. All of these offerings were done in thankful, believing response to what God has done and what He has given. They were not good works seeking favor, since Grace was already given. They were done for the worshipper to remind and remember, to thank and praise, to believe and receive.
God does not forgive because you made a sacrifice. He forgives because Jesus made the sacrifice. Worship, thanks, praise, prayer, giving, loving, serving, and doing good works are all offerings and sacrifices that we do in response to what God has done for us. Our whole life is response to God; our family, friends, and neighbors get the benefit.
We go to church to receive the blessings of God by means of the Gospel. For this reason church worship is more properly called Divine Service (God’s service to us, not our service to Him). Worship is our response, celebrating His Gifts and Service. So for the OT believers the daily sacrifices and seasonal feasts were to remember and receive God’s Promise of a Savior. The sacrificing was done for the worshipper’s benefit, not for God’s; it reminded him of the Gospel.