That is from the book of Matthew, it is a warning that the most important people on earth will be last in heaven. Simply put, being rich, successful, or famous without serving others is not a plus, what counts in heaven is what you have done or refused to do for each other while on earth. It is the reason that Christian based charities help everyone, their life choices, religion etc, none of it matters more that fulfilling their daily needs, everyone is a child of the same God, reward or punishment is left to him alone.