What does it mean to walk into the shadow of death?

I have posted this in my facebook account: 

What does it mean to walk in the shadow of death? When I seem hopeless and abandoned, & when that despondency descend on me, I plunged into that leap of faith, throw myself into the hands of God my Savior, knowing that He who is my maker will not abandon me. For the chastisement of God is medicine and His Mercy a healing balm.  

The psalmist in the Old Testament has poetically described the life of a believer as someone walking in the shadow of death.  What does it really mean to walk in the shadow of death without undergoing death itself.  We we were born into this world for a purpose no doubt.  For even Our Lord Jesus said that the smallest bird in the sky will never fall unless it has the permission of God our Father.  That even our hairs are numbered.  This reality may seem difficult to grasp because of our finiteness.  But to simply put it everything is under the control of God.  We make a lot of choices and God gave us freedom to choose.  To a large extent what ever happens to us is the product of our own making.  But to walk in the shadow of death means to be confronted by our limitations and finiteness.  Thus often we descend on despondency.  But this condescension to despondency is an invitation for us to pluge ourselves into that level of trust - the ultimate test of faith.  Faith is an act of grasping however we do not see what we are grasping us but it is an invisible assurance of what we hope for.  To some extend faith is a human act because we have to will it, but ultimately it is a gift that only God Almighty can give.  It is an act of Grace.  God will give it to those that asks for it in humility and submission to His Will.