Answer... 

TORAH (and Pentateuch)... 
Genesis, Exodus, Leviticus, Numbers and Deuteronomy

Why it matters? (Why do you think it matters?)
These writings were so important that they were passed on from generation to generation long before they were written on scrolls. 

Now What?
Just note that these are the most sacred writing in the Judaism.

Jesus would have known the Torah well. 

Bonus - Five More Minutes

Hebrew Scriptures