This is a sad song about a person who needs love but she can't get it. The video shows an antidote for this loneliness: share your love, hug people.

HALLELUJAH= (alternative spellings: Halleluyah, and the Latin form Alleluia ) A religious word of Hebrew origin meaning "praise be to God". It is used to praise God, and also to express great joy.

CHORD= /kɔ:*d/ This word used to refer to the strings of a stringed instrument, like a guitar or a harp. Today we use it to express a kind of melody created with those instruments (in this case, David's harp). In this song, A SECRET CHORD means "a secret melody (that David played with his harp)".

DAVID= A little young shepherd, born in Bethlehem. Still quite young, God chose him and he became King David, the second king of the Israelites and its most important king ever. He was also a great sinner and a great saint, the perfect example of how an incredible man can fall down and get up again, and fall down, and get up again and again. He was also a distant ancestor of Jesus and reigned around the year 1000 BC. He is the one who unified all the Israelite tribes in one single kingdom and set its capital in Jerusalem, turning this little town into the political and religious capital of Israel. He was also a great musician and composed many songs to praise God, many of them compiled in the Book of Psalms of the Bible and still sang today very often in Jewish and Christians religious services, 3,000 years later.
His most famous deed was when, still a young boy, he killed Goliath, a huge Philistine warrior, throwing him a stone with his sling.
His most terrible sin was when he fell in love with Bathsheba, a beautiful woman that he saw from his palace room when she was having a bath. He ordered his husband, Uriah, to be sent to the battle in a most dangerous position, so he was killed and he could marry her.
Still, every time he fell into sin, he turned back to God and claimed for his mercy, again and again, that's why God loved him so much, not because he was good and perfect, which he wasn't, but because David's repentance was even bigger than his sins.

IT PLEASED THE LORD= God liked it.

YOU DON'T CARE= You don't think it's important or interesting.

DO YA?= Do you?
The form "ya" /jə/ is a colloquial spelling to reflect the colloquial pronunciation of "you".
Question tags (, auxiliary + pronoun) are used at the end of a sentence when we need confirmation because we are not completely sure. When the sentence is affirmative the question tag is negative, when it's negative the question tag is affirmative:
+ - She's rich, isn't she? (= tell me yes or no, I'm not completely sure)
- + You don't like her, do you? (= I think you don't like her but I need confirmation)
But we can also use a question tag even when we are sure that what we said is correct. In that case, the intonation is not rising like in questions, but falling, and we use the question tag just to press the listener to say something, whatever.
- + You don't care, do you? [falling intonation] (= I know perfectly well that you don't care)
This second type of question tags is the one used here in this line ("but you don't really care for music, do ya?")

IT GOES LIKE THIS= This is how it sounds.

THE MINOR FALL...= The line "the fourth, the fifth, the minor fall and the major lift" has a double meaning. On the one hand it describes the melody using musical technical words. On the other hand, after mentioning King David, it's easy to think of this as a series of falls and repentances ("lift" is "elevate", get up, "minor" also means "not very important" and "major" means "very important"). Since this song is about love, this talks about problems or infidelities and subsequent repentances (to repent is to genuinely feel sorry about something wrong you did and to ask for forgiveness)

THE BAFFLED KING= A new reference to King David. BAFFLED means "confused, perplexed, that can't understand the situation". David was baffled because he couldn't understand why he was falling again and again when he wanted to be always good and perfect (but he was too weak).

PROOF= Since we are still talking about King David, this line says that David's faith was strong but still he needed God to prove him that He was real and loved him (this doesn't come from the Bible but suits the metaphor in this song). But the song uses biblical imagery to talk about a love relationship between a man and a woman, so this is the man asking the woman to prove her love.

YOU SAW HER BATHING ON THE ROOF= A reference to Bethsheba, the woman that King David saw from the roof of his palace when she was having a bath and he fell in love with her, but she was married. So David ordered her husband Uriah to be sent to the most dangerous position in a battle so he was killed and David married her (roofs in Palestine were, and still are, flat, because it rarely rains there, so people can go up there and do things on the roof, like bathing, hanging clothes, or resting or chatting with friends).
The following lines make a reference to how this woman was King David's ruin, but at the same time, since we are really talking about a love relationship, this is used to describe an infidelity and how it destroys the relationship.

OVERTHREW= (over- throw-threw-thrown) To destroy.
The line "her beauty and the moonlight overthrew you" means that you fell in love with her because she was beautiful and everything was very romantic ("the moonlight", though in the Bible it says it was in daylight) so you fell in love with her, and that caused your fall, your destruction. The next line, with a reference to the kitchen chair, is not part of the Bible either.

SHE BROKE YOUR THRONE= She destroyed your power (the throne is the place where a king sits to rule, so it is a symbol of the king's power and authority)

SHE CUT YOUR HAIR= She destroyed your strength and your power.
This is another biblical reference to Samson, a biblical character who also fought the Philistines. It was said that he had a supernatural strength, but that strength was in his hair. He never cut his hair to preserve his strength, but the Philistines arranged for a beautiful woman to seduce Samson, and when he was asleep, she cut his hair and he lost all his strength, so the Philistines could capture him.

DREW= (draw-drew-drawn) If you draw something, you extract it, you take it out.

ABOVE= /əbʌv/ Over us, high up there.

WHO OUTDREW YA= (draw-drew-drawn) Who has outdrawn you.
"Outdrew" means "to draw out, to extract" or in this case, "to take your gun out before somebody else's does". This expression comes from duels in the American West, when two guys have to shoot at each other, and the one who takes his gun faster is the one who will probably kill the other. So what she says "all I've ever learned from love was how to shoot somebody who outdrew ya" = I've learned to hit before I was hit. That means that she has never known true love, all her experiences have been very bad and she had to learn how to defend herself from other men who were always trying to hurt her. She needs love, but she has never found it yet.

IT'S A COLD AND IT'S A BROKEN HALLELUJAH= This last sentence summarises all the meaning of the song. The exclamation "hallelujah" is used when we are very happy or overjoyed. She would like to feel happy too, but she's suffering so much that even though she tries to say "hallelujah", her cry is cold and broken, because there is no love in her life.