Psalm 42:9

I say to God my Rock, "Why have you forgotten me? Why must I go about mourning, oppressed by the enemy?"

I say to God my Rock 
Psalm 18:31  For who is God besides the LORD? And who is the Rock except our God?

Why have you forgotten me? 
Psalm 10:11  He says to himself, "God will never notice; he covers his face and never sees."

Why must I go about mourning 
Psalm 35:14  I went about mourning as though for a friend or brother. I bowed my head in grief as though weeping for my mother.

oppressed 
Job 20:19  "For he (the godless person) has oppressed the poor and left them destitute; he has seized houses he did not build."
Psalm 43:2  You are God my stronghold. Why have you rejected me? Why must I go about mourning, oppressed by the enemy?
Psalm 106:42  Their enemies oppressed them and subjected them to their power.

by the enemy 
Psalm 9:13-14  LORD, see how my enemies persecute me! Have mercy and lift me up from the gates of death, that I may declare our praises in the gates of Daughter Zion, and there rejoice in your salvation.

(parentheses are mine)

Scriptures taken from the Holy Bible, New International Version® NIV®, Copyright© 1973, 1978, 1984, 2011 by Biblica, Inc.® Used by permission. All rights reserved worldwide. 
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