I ALWAYS TRUST IN YOU MY DEAR JESUS

Who Am I?
Today and always I want something that has not cost, but it is very valuable.
It is given all over the world and speaks all languages.
On its name, kingdoms have been conquered but also betrayals have been shown.
It is the only thing that the one who has everything asks for.
You give everything you have on its behalf; and it is the only thing you leave when you die.
Either in the silence, or in the rhythm of a song, it is the best memory that you keep in your heart.
Everyone talks about it, but very few really know it.
I am Who I am, Who am I?