While they were there, the time came for her to give birth.” (Luke 2:6 NASB) 

“There is an appointed time for everything. And there is a time for every matter under heaven—

A time to give birth and a time to die;
A time to plant and a time to uproot what is planted.
A time to kill and a time to heal;
A time to tear down and a time to build up.
A time to weep and a time to laugh;
A time to mourn and a time to dance.”
(Ecclesiastes 3:1-4 NASB)

“So, Sarah conceived and bore a son to Abraham in his old age, at the appointed time of which God had spoken to him.” (Genesis 21:2 NASB)

There is an appointed time for everything.

God appointed Mary’s time to deliver the Savior, and Sarah’s time to give birth to Isaac. God Almighty set these dates and those that are to come. There is an appointed time known only to God. His Son sits beside Him waiting to be called. We will never know the day or hour until it comes to pass, but it’s enough to know that Jesus will return at God’s appointed time.

“Now to Him who is able to protect you from stumbling, and to make you stand in the presence of His glory, blameless with great joy, to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion, and authority before all time and now and to all the ages. Amen.” (Jude 1:24-25 NASB)