While Psalm 90 is not first in the book of Psalms, it is actually the first psalm written, penned by Moses. He reflects on how God has always been faithful to His people, even when they were unfaithful to Him.
Can we always trust what our conscience tells us? What do we do with our guilt and shame? In Psalm 51, we hear the repentant heart cry of King David after he is confronted with his sin of adultery and murder.
There are times when we come to God with an attitude that we're owed all the good things of life. This is how the psalmist in Psalms 73 approaches God, but his heart is changed when he sees that the things of this world are fleeting and his only true refuge is in God.
While most of the Bible is God speaking to people, in the Psalms, we find people responding to God and the circumstances of life. In Psalm 27, we see King David facing his adversities; a reminder to us that even though everything around us might fail, God will never forsake us.