From Orthodox catechism
In the first day there are more reasons to celebrate:
it is sunday - the day of the sun - the first day when sun arised
(Genesis 1:3 And God said, "Let there be light," and there was light.)
(not in catechism, Muke comment -> false assertion)
- In this day He created the univers - one verset -
Genesis 1:1 In the beginning God created the heavens and the earth.
- Is the day when the Lord Jesus Christ rise from death, the day when death was defeated for the human nature.
Matthew 28:1 After the Sabbath, at dawn on the first day of the week,
Mary Magdalene and the other Mary went to look at the tomb.
The true reason.
- Is the day when Holy Spirit come down to the earth in the day of pentecost
Acts 2:1,3 When the day of Pentecost came, they were all together in
one place. Suddenly a sound like the blowing of a violent wind came
from heaven and filled the whole house where they were sitting. They
saw what seemed to be tongues of fire that separated and came to rest
on each of them.
Everybody could observe, not only that the Lord Jesus choose the first day to bring us the good news.
Also, the Holy Spirit choose the same first day to come to us.
What kind of Christian could ignore these proves and to not take the first day as the day of joy?!
- Is the day of first liturgy, the day when first christians "break bread"
Acts 20:7 On the first day of the week we came together to break
1 Corinthians 16:2 On the first day of every week, each one of you
should set aside a sum of money in keeping with his income, saving it
up, so that when I come no collections will have to be made.
The first day is called Lord's Day. What day we can celebrate other than Lord's Day?!
Revelation 1:10 On the Lord's Day I was in the Spirit, and I heard
behind me a loud voice like a trumpet,
In my opinion (which is not so important) the 10 commandments must be understood in their context.
The context was that, the Jewish people, after spending centuries in Egypt, became seek with egyption disease: idolatry.
They were so seek, because after they saw the miracles from the dead see, at short time after, the same people with same eyes and minds, made a calf from melted metal thinking to it as the savior from the Egyptian's hands.
Today for us seems to be very unbelievable to embrace this kind of illusion. (meanwhile God teach us and cured us.)
So God, gave them a reason to not forget and to not delude their-self with illusions, and to remember Who is their savior and protector, by celebrating the seven day as a law.
But we today what to remember? The Sabbath? The exod of Jewish people? This is not so clever. We have more important reasons to celebrate, to remember, directly regarding to us.
To understand that God cured us (in the first day), we should not forget that the same kind of idolatry (illusion) was very spread 2000 years ago.
The most civilized cultures, Greek and Roman, had many gods in that time: gods for everything: for food, for water, for fertility, for beauty, for hunt, for war etc.
How they dissapeared in 300 years? What happened?
The answer: God make a fire to Golgotha. And the martyrs spread that fire around the world.
Through apostles, God bring civilization, hospitals, schools teaching us real wisdom and philosophy of the life: Christianity.
Not pitagoreic schools, or previous academies, neither followers of Socrates.
So, we celebrate the rise from death of the Lord of the life, Jesus Christ.