What is the usage in Psalm 23 of “through” the valley of the shadow of death?
So is this understanding of the word through, to include "coming out of" reasonable from the original text?
Yes, it is reasonable as it is implied in the contextual meaning of the verse.
The Aramaic Bible in Plain English translates the verse as follows.
"Even if I shall walk in the valleys of the shadows of death, I will
not be afraid of evil, because you are with me; your rod and your
staff, they comfort me,"
The psalmist David declared:
Psalm 23:4: (NIVUK)
"Even though I walk through the darkest valley, I will fear no evil,
for you are with me; your rod and your staff, they comfort me."
As a young boy, David was a shepherd and became familiar with the dangers that faced his sheep. Wild beast lurking in the dark valleys, pandits lying in ambush, and deep pits. Without the attention and care of the shepherd the sheep would be in great danger. A shepherd would use his rod and staff to direct and defend his flock.
David in this verse is talking about how God helps him to endure adversity when his life was in danger, it as if he" walked in the valleys of the shadows of death" When God helped David to kill the giant Philistine, Goliath, Saul developed a deep hatred and tried on many occasions to kill him. (1 Samuel 18:11 , 19: 9- 10). Because of Saul's incessant efforts to capture and kill him, eventually, David was forced to seek refuge outside the territory of Israel.
Since God was his shepherd and guiding him, protecting him figuratively with his rod and staff, David felt comfort that God was with him, protecting him, and so did not give way to unrestrained fear.
"Even though I walk through the darkest valley"
Job 38:17 (NASB) “Have the gates of death been revealed to you, Or
have you seen the gates of deep darkness?
"I will fear no evil."
A Psalm of Fearless Trust in God.
Psalm 27:1 (NASB) "The Lord is my light and my salvation; Whom
shall I fear? The Lord is the defense of my life; Whom shall I dread?
"for you are with me; your rod and your staff, they comfort me."
Isaiah 43:2 (NASB)
“When you pass through the waters, I will be with you; And through
the rivers, they will not overflow you. When you walk through the
fire, you will not be scorched, Nor will the flame burn you."