Question: What is the meaning of life in Islam? 

Answer: Life is a test for the Hereafter 

Question: What is the meaning of death in Islam? 

Answer:  Death means the end of the test in this world, and beginning of eternal life in the Hereafter 

Question: What is the purpose of human life in this world?  

Answer: It is to establish a good relationship and friendship with God.

Question: Is belief in God and performing rituals enough in order to pass the test of this life? 

Answer:  No, one must also lead a proper moral life?   

Question: What are the consequences of not believing in life after death? 

Answer:  It leads to nihilism where nothing has ultimate objective purpose or meaning.  The absence of ultimate meaning and purpose is the strict definition of nihilism.