Psalm 49 is a wisdom psalm.  It explains why the pious often deal with trouble, while in contrast, the unfaithful seem to get along so well in life.  The short answer is that God will distinguish between the faithful and the unfaithful after their death.  

1-4 – Here is a call to pay attention to attain wisdom and understanding, which is often used in Wisdom Literature to mean spiritual perception, the ability to approach life from God’s perspective.  The singer states that he will do this by solving a riddle.

5-12 – The riddle is presented, which, as stated above, is the question of why the faithful have times of trouble, while the unfaithful always seem to prosper.  The unfaithful trust in their wealth, yet they are not wealthy enough to ransom their lives from death.  All of the wealth of the unfaithful is left to others.  The unfaithful will die just as the faithful will someday die.  Then the Psalm explains what happens after death.

13-20 – The singer tells us that after death the unfaithful will be sent to Sheol, a grim place of destruction.  The unfaithful dead will be in an unnatural situation of having a soul unattached to a body.  In contrast God will ransom the soul of the faithful from Sheol.  Here we see future reference of Christ’s death on the cross that paid the ransom for our sins.  Instead of Sheol, the faithful after death will live in glory with God.  The implication is that the faithful will have new bodies in glory with God.