Psalm 151
Psalm 151 is recognized as Deuterocanonical Scripture by the Greek Orthodox and Russian Orthodox Churches.
This Psalm is a genuine one of David, though extra, or, supernumerary composed when he fought in single combat with Goliath.
I was small among my brothers,
and youngest in my father’s house.
I tended my father’s sheep.
My hands formed a musical instrument,
and my fingers tuned a lyre.
Who shall tell my Lord?
The Lord himself, he himself hears.
He sent forth his angel and took me from my father’s sheep,
and he anointed me with his anointing oil.
My brothers were handsome and tall;
but the Lord didn’t take pleasure in them.
I went out to meet the Philistine,
and he cursed me by his idols.
But I drew his own sword and beheaded him,
and removed reproach from the children of Israel.

^ or, supernumerary