It is truly just and right to the majesty of Your holiness to praise You, to hymn You, to bless You, to worship You, to give thanks to You, to glorify You, the only true God, and to offer to You this our spiritual worship with a contrite heart and a humble spirit.
(Divine Liturgy of St. Basil, p. 23)
Bless Him, all who worship the Lord, the God of gods, sing praise to Him and give thanks to Him, for His mercy endures forever.
Song of the Three Young Men 1:68
The experience of worship for Orthodox Christians is ancient, sensory, and unique. The idea of worship comes from the Old Testament, all the way back to the Creation of the world. In creating the world, God blessed the seventh day and hallowed it as a day of rest, a Sabbath. We read in Genesis 2:2-3: “And on the seventh day God finished His work which He had done, and He rested on the seventh day from all His work which He had done. So God blessed the seventh day and hallowed it, because on it God rest from all His work which He had done in creation.”
Therefore, as St. Basil writes in this prayer, “It is truly just and right to the majesty of Your holiness to praise You, to hymn You, to bless You, to worship You, to give thanks to You, to glorify You, the only true God.” It is not only truly just and right to do these things, but it is a commandment of the Lord, originating on the seventh day of creation, and written into the Ten Commandments, that we are to “remember the Sabbath day, to keep it holy.” (Exodus 20:8) Incidentally, this is why Jesus was crucified on a Friday, the sixth day of the week, the day that God had finished the creation, so that Jesus rested in the tomb on the Sabbath. And when the Sabbath had passed, He rose from the dead, and inaugurated a new Sabbath. The Greek word for the first day of the week is “Kyriaki,” which literally means “The Day of the Lord” (The word “Kyrios” in Greek means “Lord”). And now our day for the Lord is the first day of the week, rather than the last one. We are supposed to reserve each Sunday as a day of the Lord, made holy to Him as a solemn day of worship, and also a day of rest.
“Our spiritual worship” has changed over time. In the Old Testament, worship was based on ritual sacrifice on an altar. The first mention of this is in Genesis 8:20, where we read “Then Noah built an altar to the Lord, and took of every clean animal and of every clean bird, and offered burnt offerings on the altar.” There was a ritual of sacrifice, but not a standardized service or tradition to accompany it.
In Exodus, the Passover inaugurated the concept of a regular worship to commemorate an event. Before Moses led the Hebrews out of Egypt, the Passover was instituted, which actually prefigures Christ and the Eucharist. The Hebrews were slaves to the Egyptians for hundreds of years. God called Moses to go before Pharaoh, the leader of the Egyptians, and demand that the people be let go. Pharaoh refused, and a series of plagues came over the land of Egypt. After each of the plagues, Pharaoh said he would let the people go, but then his heart hardened, and he would not.
God, through Moses, gave specific instructions to the Hebrews that the angel of death would “pass over” the land of Egypt, killing the first born of everything in the land. This would be the tenth and final plague. The people were to take lambs without blemish, and kill them outside the city wall, not breaking any of their bones. The blood was to be placed on the doorposts of each house, and the blood would cause the angel to “pass over” these homes. And God told the Hebrews in Exodus 12:24 that “You shall observe this rite as an ordinance for you and for your sons forever.” (Exodus 12 gives an account of the details of the first Passover) This prefigures Christ, in that He is the lamb of God, killed at Passover, outside the city wall, with none of His bones broken, without blemish, and by His blood, shed on the Cross and now received in the Holy Eucharist, we are able to pass over from death to eternal life.
After the Exodus, God gave Moses the Law, which instructed how and when the people were to worship and rest.  In addition to the aforementioned commandment to remember the Sabbath, the Law provided for the creation of a sacred space in which the covenant was to be stored, an “Ark”. The Ark of the Covenant had a mercy seat on it, and God said this would be the place where He would speak with the people. (Exodus 25:22) The ark was carried in front of the Hebrews every time they moved their camp. It was tended to by a group of priests, who came from the tribe of Levi, one of the twelve tribes of Israel. Eventually, the ark was placed in a temple in Jerusalem that had been built by King Solomon. (I Kings 8) The thought was that God resided in the temple, and people went to the temple regularly to worship Him and continued to bring sacrifices to Him.
Jesus changed the concept of worship. Worship was no longer tied to a sacrifice requiring the shedding of blood. He shed His blood for us. We are not required to shed any blood for Him. The posture of worship is no longer a posture of sacrifice and suffering of anyone. Rather, what is needed now for “our spiritual worship” is a “contrite heart and a humble spirit.” We are to come with humility, reverence and preparation. Most important, we are to come with joy.
It is true that we worship in elaborate temples, with ornate décor. However, at the heart of worship is a contrite heart and a humble spirit. The contrite heart is the one that has a hunger for God, and an awareness of a need for repentance and continued growth towards God. The humble spirit is the one that places God and others above himself or herself. The humble spirit is not concerned with self-aggrandizement, but with giving glory to God while joyfully serving others. This is the background, both from a historical perspective as well as a spiritual demeanor, that sets the stage for our worship of God and our eventual partaking of Him in the Eucharist.