"Mary, Did You Know?" is a Christmas song with lyrics and music written by Mark Lowry and Buddy Greene in 1991. The song has since gone on to become a modern Christmas classic, being recorded by many artists over the years across multiple genres. This here is the acapella version by Pentatonix.

Mary, did you know
that your Baby Boy would one day walk on water?
Mary, did you know
that your Baby Boy would save our sons and daughters?
Did you know
that your Baby Boy has come to make you new?
This Child that you delivered will soon deliver you.

Mary, did you know
that your Baby Boy will give sight to a blind man?
Mary, did you know
that your Baby Boy will calm the storm with His hand?
Did you know
that your Baby Boy has walked where angels trod?
When you kiss your little Baby you kissed the face of God

Mary, did you know? Mary, did you know?
Mary, did you know? Did you know?
Mary, did you know? Mary, did you know? Mary, did you know?
Mary, did you know? Mary, did you know? Mary, did you know?

The blind will see.
The deaf will hear.
The dead will live again.
The lame will leap.
The dumb will speak the praises of The Lamb.

Mary, did you know
that your Baby Boy is Lord of all creation?
Mary, did you know
that your Baby Boy will one day rule the nations?
Did you know
that your Baby Boy is heaven's perfect Lamb?
That sleeping Child you're holding is the Great "I Am".

Mary, did you know? Mary, did you know?

Mary, did you know? Mary, did you know? Mary, did you know?
Mary, did you know?

Mary, did you know?

Mary, did you know
that your Baby Boy would one day walk on water?
Mary, did you know...

MARY= Jesus Christ's mother.

DID YOU KNOW... YOUR BABY BOY WOULD...= We can use the verb WOULD as the past of WILL in some contexts, especially when there is an introductory verb in the past (as in reported speech, etc.).
Present—I will find my lost book.
Past—I didn't know that I would find my lost book.
Present – Your child will walk on water.
Past—Did you know that your child would walk on water?

SAVE= In religion, the word "save" is often used with the meaning of "liberate", "set free". In Christianity it has a spiritual and a social meaning, because the Kingdom of God is both spiritual and social (it is a Kingdom for the Heavens and the Earth).

TO MAKE YOU NEW= To change you into a new person, to change your life.

DELIVER= This verb has two meanings, and in this line it is used in both meanings:
1- to give birth (e.g. She delivered a beautiful baby boy at the hospital)
2- to save us, to liberate us (in a religious sense) (e.g. Father, deliver us from evil. Jesus delivered us = He saved us).
So Mary delivered(1) Jesus, and Jesus delivered(2) Mary.

SIGHT= The ability to see. Vision.

BLIND= A blind person is someone who can't see.

CALM THE STORM= A famous miracle of Jesus was when they were on a boat in the middle of a terrible tempest and he ordered the storm to stay still, and the storm stopped.

TROD= Tread-trod-trodden = step, walk on. The expression "to walk where angels trod" means to lead a way of sanctity, to be a saint. But here it is also used in a literal sense, because Jesus was in heaven, where angels are, so he literally had trodden where angels tread.

THE DEAF= In English we can use the article THE + ADJECTIVE to refer to a special group of people.
The blind = people who can't see
The deaf = people who can't hear
The lame = people who can't walk
The dumb = people who can't speak

THE LAMB= Jesus

THE NATIONS= The world, all the countries, all kinds of people and cultures.

HEAVEN'S PERFECT LAMB= Ancient Jews used to sacrifice a lamb to redeem their sins. By accepting death, Jesus became the perfect lamb for the sacrifice, and he redeemed the sins of all humanity forever, so sin no longer had the power to kill our soul.

YOU'RE HOLDING= You have in your arms.

THE GREAT "I AM"= God.
In ancient times, the nations had different gods, many. Every god had a name. The first nation to believe that there was only one God were the Hebrews (modern Jews). There was only one God and so He needed no name.
When the prophet Moses saw God in the burning bush, he asked Him His name, but the name defines a person, and God is impossible to define, so God simply replied more or less: "I am who I am" (which in Hebrew is: "Yah weh", "I am". So "Yahveh", or the misspelling "Jehovah" is not really a name but a title or a description). When the song says "He is the Great I am", it means "He is God".

For those not familiar with Christian faith, I'll explain a few things here to help you understand the song.

Christians believe that Jesus is the son of God. What's more, Jesus is God Himself, incarnated. So the song wonders if Jesus' mother realized all this when He was born.

Jesus made many miracles, most of them had a social intention (the Bible usually calls them "signs", so they are like a message without words), for example He cured the blind so that they could see (His message made people know the truth, help them understand). Other famous miracles are described in the song: He walked on water, cured the deaf, the lame, the dumb and rose the dead back to life. He died to deliver us (to save us from death, evil and social oppression).

According to ancient Jewish rituals, lambs were sacrificed to God in order to pay for our sins. When Jesus offered His own life to compensate for all our sins, he turned Himself into the perfect Lamb, the ultimate compensation (that's why He's often called "the Lamb of God"). Of course, he was killed because he was trying to liberate the poor from political oppression and for trying to purify a religious system that was, at that time, completely corrupt and oppressive itself. But His death was our ransom, the price for our delivery (our salvation), and His message can still inspire people to look for a better world (even at the risk of losing their life). His resurrection is the proof that he defeated Death, and the promise that we will all resurrect one day too.