Lyrics i love, but dont quite get!!!

I was listening to some retro in the middle of (yet another) long traficcy drive home... stuck in the worst jam (Are there any other kind of jams) of the century, when i heard two of my fav. songs...
Given that they were old numbers id heard countless times, i realized that i hadnt paid much attention to the lyrics - at least for the first one. Which is quite poetic, and filled with, if i may say - hopeful despair!!! By U2, its a number called...i still haven't found what im looking for... The first two paras (Edited for repeats) are poetic... and read as below

I have climbed the highest mountains
I have run through the fields
Only to be with you
I have run I have crawled
I have scaled these city walls
Only to be with you
But I still haven't found
What I'm looking for

The next segment gets all holy or im yet to understand the non-religious allusions to lyrics like "kingdom come", "you carried the cross", "tongue of angels"

The other one
Simple song, or is it....speaks of being unfaithful despite being in love... Used to think it was a super duper romantic number till i paid close attention today...now its more - "You men" than romance:)
"Leaving on a jet plane"
The romance begins

All my bags are packed down, i'm ready to go,
i'm standing here outside your door
i hate to wake you up to say goodbye
But the dawn is breaking,it's early morn
The taxi's waiting, he's blow his horn
Ai'm so lonesome i could die

And the "oh you men" part... to be fair ,it can be directed as "oh you women" as well - Janis joplin did a cover of this anyways...so here goes
There's so many times i've let you down
so many times i've played around
but darling now they don't mean a thing
every place i go i think of you
every song i sing i sing for you
when i come backi'll wear your wedding ring...
Yeah right... But they still remain on my all time fav. list...