Hi Faddy:
The hymn is " We Will Understand it Better By and By"
The first verse is
Trials dark on every hand and we cannot understand
All the ways that God could lead us to that blessed promised land,
But He'll guide us with His eye and we'll follow till we die
We shall understand it better by and by.
Temptations, hidden snares often take us unawares,
And our hearts are made to bleed for a thoughtless word or deed;
And we wonder why the test when we try to do our best,
But we'll understand it better by and by.
The lines you quoted above are the refrain (you got it all right).
Here is a link to the comple song, but I've never heard the first two verses. To me it starts with the third verse.
http://www.cyberhymnal.org/htm/w/e/welunder.htm
Regards
Neil