LOOK DOWN...= This song is inspired by one day he was at the airport watching people passing by, same as so many times before. They are all strangers, part of the furniture, nobody really, as usual. And suddenly he feels that for God, each and everyone of those persons are important, are sacred, are unique and have a life of their own, are valuable, are loved. So he is asking God to give him His eyes so he can see them in the same way. The first two stanzas (paragraphs) in the song are describing the airport situation: First he is on the plane, LOOKING DOWN from a sky which looks broken by the city lights a mile down from him. He has the BEST SEAT IN THE HOUSE TONIGHT (he's travelling first class). Then the plain TOUCHES DOWN (lands, touches ground) ON THE COLD BLACK TOP which is the tarred runway (the track or "road" where the plain lands). He HOLDS ON (waits) for the sudden stop that happens when the plain finally stops and he is BREATHING ( /bri:ðɪŋ/ feeling around him) the FAMILIAR (usual, known) chaos than is always going around at the airport.

CHAOS= /keɪəs/ A condition or place of great disorder or confusion.

CARED= /keə*d/ If you care about something, you think it's important and pay attention to it.

GIMME= /gɪmɪ/ (coll.) Give me.

YOUR EYES= He's talking to God, so when he says "gimme Your eyes" he means "let me see the world, the people, in the same way as you see them".

SO I CAN SEE...= So that I can see.
This is a purpose sentence, expressing the reason why you want something.
One subject:
- I want to open the door to enter (I want / I enter)
Different subjects:
- I want to open the door SO THAT you CAN enter (I want / YOU enter)
As you can see, when the subjects are different we don't use TO, we use SO THAT + 2nd subject + CAN (or: will/may, or: could/would/might for the past). But in colloquial English it is very common to drop the THAT, and instead of using the connector SO THAT we simply say SO + 2nd subject + CAN.
- Gimme your eyes so I can see = God, please, give me your eyes because I want to see.
The complete sentence here is : "Gimme your eyes so I can see everything that I keep missing".

KEEP +ing= Continue.

MISSING= If you are missing something, you can't see it, you don't know it exists, or you are not experiencing it.

HUMANITY= The human race, all the people.

THE BROKEN HEARTED= People with a broken heart, people who are suffering.
We can use THE + ADJECTIVE to refer to all the people who have that quality:
- the poor = people who are poor.

FAR BEYOND MY REACH= Too far away for me to reach. FAR is here an emphasizer (like "very"). BEYOND= farther away. MY REACH= my capacity to touch it. If something is beyond your reach, you can't touch it or get there or experience it. If it is FAR beyond your reach, it's really impossible for you to get it. The opposite is "within my reach", if womething is within your reach it is accessible for you, you can touch it or get it.

STEP OUT= Go out (walking). If you step out on A BUSY STREET, you get out of your house (walking) and into a street with many people walking and driving fast.

OUR EYES MEET= Our looks meet: I look at her and she looks at me at the same time.

DOES HER BEST TO SMILE= She tries hard to smile, she makes a big effort to smile. If you do your best, you make every possible effort to do it.

UNDERNEATH= Below, under the surface (in this case, inside her heart).

TIE= (see picture)

ASHAMED= If you are ashamed you feel embarrassed, very uncomfortable.

OUT OF WORK= Unemployed.

HE'S BUYING TIME= He is trying to postpone it, to do it later, not now.

I SWEAR...= To swear is to declare or affirm solemnly by invoking God as a witness. But most of the times we use this word just to emphasize that what we say is true, so "I swear I never thought..." means "I really never thought..., you must believe me, it's true".

GLANCE= A quick look. If you want a second glance, you want to look at it again.

ALL ALONG= All the time, always.

LORD= God.