The Heresy of Cain and Independence Day

One author wrote that when God approached Cain and asked him, Where is your brother Abel?, Cain committed a heresy, when he answered, I do not know. Am I my brother’s keeper? The author continued that to many Americans, Independence Day is a day to celebrate their liberation from having to be our fellow’s keeper, our independence from others. He said that the Cain Heresy is alive and well in our culture, threatening to totally devour the freedom it claims to defend. What about it? Does the Bible say that we are to be our brother’s keeper? And if so, how?