Valleys are symbolic of winds that blow, going slow, and feeling low.  Valleys are often the places we most frequently forget the incredible gifts God has poured into and onto us in Christ.  The writer of Hebrews writes to people that had chosen to follow Jesus but began to experience valley living.  The valleys  were so deep for some of the people that they were walking away from Jesus.  But rather than excoriating people for leaving, the writer reminds them of what they had forgotten: what does it profit a person if they gain the whole world but lose their soul. And within the 13 chapters of Hebrews, the writer reminds the Hebrew Christians why the pursuit of Jesus, and Jesus alone, can fulfill their souls.