In the past, when I've thought of the birth of Jesus, I've typically thought in terms of miracles and great divine intervention. However, as I was reading through Matthew's gospel lately, I found that this isn't the case entirely.
Obviously the birth of God--God taking on flesh and dwelling on earth, the creator living like a creature--is no small matter. It is a wonder on many levels (he said with immense understatement). But many of the events surrounding Jesus' birth are NOT miraculous. In fact, many of the events played out as they did because God spoke and people listened and then acted accordingly.
Let me give some examples to show what I mean. First, Joseph planned on divorcing Mary when she was "found to be with child." But while he was thinking about this, an angel of the Lord appeared, explained the situation, and told him to marry her. What did Joseph do? "He did as the angel of the Lord commanded him."
Secondly, when the wise men came to see the babe Jesus, Herod told them to send word when they found the child, so he could "come and worship him" too. They went to see Jesus and "rejoiced exceedingly with great joy" when they found him, but they did not report back to Herod. Why? Because they were warned in a dream not to return to Herod. They obeyed and went back to their country by "another way."
The wise men's trickery enrages Herod, and he sets out to kill all the babies age two and under. To protect the baby Jesus, God doesn't snatch him out of harm's way or cause Herod to be blinded or killed or dumbfounded. Rather, he sends an angel to Joseph again, warning him to flee to Egypt. Joseph obeys. Then, when Herod has died, an angel appears to Joseph again and tells him to bring his family back to the land of Israel. Joseph obeys yet again, and returns to Israel, but he is wary of returning to Judea for Herod's son reigns there. So an angel appears (again) and warns Joseph to go to Galilee, which Joseph readily does.
Now what we have here is a series of dream-warnings from the angel of the Lord, coupled with human response. Had the wise men and Joseph not acted in obedience, the story could have played out very differently. Mary might have been ostracized, baby Jesus might have been slaughtered, Jesus might have been born and raised in a completely hostile environment, and several prophecies might have gone unfulfilled.
In God's good providence, he orchestrated the birth and growing up of Jesus. And he acted through the obedience of faithful people--including Mary, whom I've not mentioned in detail because Matthew doesn't hone in on her specific part of the story.
In sum, God DOES intervene in the affairs of this earth, often in obvious and miraculous ways. But most of the time along the way, he acts through his faithful ones.
May he make us such as the wise men, Joseph, and Mary.