REFERENCE 30 YEARS OLD
Genesis 41:46 And Joseph was thirty years old when he stood before Pharaoh king of Egypt. And Joseph went out from the presence of Pharaoh, and went throughout all the land of Egypt.
II Samuel 5:4 David was thirty years old when he began to reign, and he reigned forty years.
Luke 3:23 And Jesus himself began to be about thirty years of age, being (as was supposed) the son of Joseph, which was the son of Heli,