The Bible mentions individuals celebrating birthdays on two separate occasions, but both times terrible things occurred.
The first mention is in the Book of Genesis where the Egyptian king Pharaoh used his own birthday occasion to execute his chief baker, whom he was angry with. This incident happened three days after Joseph interpretation of a dream that the chief baker had. He was hung at the party just as the dream foretold. (See Genesis 40:1-23)
The next time a birthday is mentioned in the Bible, is in the New Testament in the book of Matthew where King Herod ordered the beheading of John the Baptist at the urging of his wife Herodias.
“But at a birthday party for Herod, Herodias’s daughter performed a dance that greatly pleased him, so he promised with a vow to give her anything she wanted. At her mother’s urging, the girl said, “I want the head of John the Baptist on a tray!” Then the king regretted what he had said; but because of the vow he had made in front of his guests, he issued the necessary orders. So John was beheaded in the prison, and his head was brought on a tray and given to the girl, who took it to her mother.” Matthew 14:6-11 NLT
Birthday celebrations are originally of pagan origin and came about through the practice of astrology. In the ancient times, pagan astrologers invented calendars and calculated birth dates for kings, rulers and their successors through the monitoring of the stars; they examined horoscopes and birthday omens because they thought the fate of those in positions of power would affect all society. The customs were to offer congratulations, presenting gifts, celebrating with honey cakes and lighted candles as a means to protect the birthday celebrant from the demons and to ensure his security for the coming year.
The Scriptures never refers to a servant of God celebrating a birthday. Jesus did not do it, neither His disciples. But there is also no prohibition against a Christian celebrating birthday.
What the Bible does say is,
“In the same way, some think one day is more holy than another day, while others think every day is alike. You should each be fully convinced that whichever day you choose is acceptable. Those who worship the Lord on a special day do it to honor Him.” Romans 14:5-6 NLT
In other words, a Christian believer can be fully convinced that celebrating a birthday as a special day is a good thing for them. It all comes down to this,
“So whether you eat or drink, or whatever you do, do it all for the glory of God.” 1. Corinthians 10:31 NLT
Meaning, whether or not a Christian celebrates a birthday, he or she should fill his or her time with things that glorify the Lord!