Customs vary. In the US, the custom of Mother's Day was started by a woman (I forget her name) in honor of her own mother simply because she thought she was a great Mom. The woman had probably never heard of Cybele or Rhea. But in other cultures, the origin is no doubt different.

Of course we should honor our mothers everyday. But since in the United States, it is the custom to express some appreciation for one's mother on Mother's Day, is it really violating any Bible principle to do so in some appropriate way?

We remember that the Lord told the Israelites to celebrate a special festival of ingathering and thanksgiving. There doesn't seem to be anything wrong with expressing thanks or giving due honor to our parents. Sometimes we need to remember that Jesus wasn't impressed with those who were "righteous overmuch".
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we celebrate "day" everyday by wake up , and celebrate "night" by sleep ,,,, do you realize it?
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As Christianity spread throughout Europe the celebration changed to honor the "Mother Church" - the spiritual power that gave them life and protected them from harm. Over time the church festival blended with the Mothering Sunday celebration . People began honoring their mothers as well as the church.

In the United States Mother's Day was first suggested in 1872 by Julia Ward Howe (who wrote the words to the Battle hymn of the Republic) as a day dedicated to peace. Ms. Howe would hold organized Mother's Day meetings in Boston, Mass ever year.

In 1907 Ana Jarvis, from Philadelphia, began a campaign to establish a national Mother's Day. Ms. Jarvis persuaded her mother's church in Grafton, West Virginia to celebrate Mother's Day on the second anniversary of her mother's death, the 2nd Sunday of May. By the next year Mother's Day was also celebrated in Philadelphia.

Ms. Jarvis and her supporters began to write to ministers, businessman, and politicians in their quest to establish a national Mother's Day. It was successful as by 1911 Mother's Day was celebrated in almost every state. President Woodrow Wilson, in 1914, made the official announcement proclaiming Mother's Day as a national holiday that was to be held each year on the 2nd Sunday of May.

While many countries of the world celebrate their own Mother's Day at different times throughout the year, there are some countries such as Denmark, Finland, Italy, Turkey, Australia, and Belgium which also celebrate Mother's Day on the second Sunday of May

Hope it works!
http://www.gcards.com/mothersday/history.html
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The holiday of Mother's Day is not from ancient Greece.
In 1907, Anna Jarvis of Philadelphia began a campaign to establish a national day for mothers.
By 1911, Mothers’ Day was celebrated in nearly every state.
President Woodrow Wilson made the official announcement proclaiming Mothers’ Day a national holiday in 1914.
The Bible tells us to give honor to whom honor is due (Romans 13:7)
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