How could the text be read and interpreted by two different readers ?

When someone reads a literary text, he or she reads from a perspective that is unique.  An older and more renowned text like Macbeth has been interpreted and evaluated through many different perspectives. 
One such perspective might choose to focus on evil and the moral flaws of humanity:  blind ambition, arrogance, violence.  Macbeth murders to gain power, and he murders to keep it.  It is his belief that this is his divine destiny, his right.  Though this is his justification for his actions, it does not absolve him from his guilt.
Another unique perspective might focus on the roles of gender.  The women in Macbeth, such as the witches and Lady Macbeth, have somewhat masculine natures.  For example, Lady Macbeth has a powerful influence over her husband.  By murdering Duncan, Macbeth hopes to win prove himself manly to his wife.  Macbeth praises her strength, saying that she is the type of woman who should only have male children.  Later, Lady Macbeth questions Macbeth's own masculinity when she rebukes him for his weak and crazed behavior upon seeing the ghost of Banquo.
When interpreting a text, readers should read through their own unique lens of experience, but also take into consideration the many other perspectives in order to gain a better understanding.