Why was baby Jesus born and wrapped in swaddling cloth, and why did the angel say that the sign that the Savior was born is when the shepherds find the babe in (1) swaddling clothes and (2) lying in a manger?
And she brought forth her firstborn Son, and wrapped Him in swaddling cloths, and laid Him in a manger, because there was no room for them in the inn. (Luke 2:7 NKJV)
And this will be the sign to you: You will find a Babe wrapped in swaddling cloths, lying in a manger.” (Luke 2:12 NKJV)
According to Jimmy DeYoung, Jewish scholar, the swaddling clothes were typically used on new-born lambs that were bred for sacrifice. The shepherd would swaddle the lamb and place it in a manger until it settled down from the birth. This would protect it from possible injury that would disqualify it as a sacrificial lamb. When the lamb calmed, it was released to feed from its mother.
To any other passerby, seeing the babe wrapped in swaddling cloths and lying in a manger may not mean much to them, except that the baby was delivered in a less than ideal and sparse location, in a hard stone cold manger. However, when the shepherds saw the baby, it would be a significant sign to shepherds who helped to care for sacrificial lambs, used in Jewish worship to take away sin.
The sign to the shepherds that Jesus was born as the Lamb of God to take away the sins of the world! Not the blood of bulls and lambs, but the lamb of God, who takes away our sins eternally.
Jesus was born to die, delivered to the world like a sacrificial lamb. He is the Son of God, yet was delivered not in palaces and wrapped fine linen, but born in a stable.
For you know the grace of our Lord Jesus Christ, that though He was rich, yet for your sakes He became poor, that you through His poverty might become rich. (II Corinthians 8:9 NKJV)
In the birth of Christ, we see the full glory of God, and the love of God for us.
For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life. For God did not send His Son into the world to condemn the world, but that the world through Him might be saved. (John 3:16, 17 NKJV)