What is the specific law or laws that exist which requires all U.S. citizens to pay federal income taxes?

Can you please cite the source, give a statute, and define the origins of laws requiring all U.S. citizens to pay federal income taxes each year?

Public Comments

1. Origin The roots of IRS go back to the Civil War when President Lincoln and Congress, in 1862, created the position of commissioner of Internal Revenue and enacted an income tax to pay war expenses. The income tax was repealed 10 years later. Congress revived the income tax in 1894, but the Supreme Court ruled it unconstitutional the following year. 16th Amendment In 1913, Wyoming ratified the 16th Amendment, providing the three-quarter majority of states necessary to amend the Constitution. The 16th Amendment gave Congress the authority to enact an income tax. That same year, the first Form 1040 appeared after Congress levied a 1 percent tax on net personal incomes above $3,000 with a 6 percent surtax on incomes of more than $500,000
2. You know, I hear about this all the time. My answer is still the same - who cares? Nothing is free: if you want public services, pay up and grow up, and get over it! If you want to freeload, fine, but don't go thinking you get any say in anything - you're a slave by your own hand!
3. Glad to oblige. (Though, technically, not all citizens have to pay income taxes each year, only those that meet certain criteria) For the income tax laws, check out: http://www.law.cornell.edu/wex/index.php/Income_tax http://www.law.cornell.edu/uscode/html/uscode26/usc_sup_01_26_10_A.html http://www.law.cornell.edu/uscode/html/uscode26/usc_sec_26_00006012----000-.html http://www.law.cornell.edu/uscode/html/uscode26/usc_sec_26_00000001----000-.html http://www.law.cornell.edu/uscode/html/uscode26/usc_sec_26_00000003----000-.html http://www.law.cornell.edu/uscode/html/uscode26/usc_sec_26_00006651----000-.html For the major acts passed by congress regarding the Federal Income Tax... Revenue act of 1862: http://www.reference.com/browse/wiki/Revenue_Act_of_1862 1894 Income Tax and the Wilson-Gorman Tariff Act: http://law.enotes.com/major-acts-congress/income-tax-wilson-gorman-tariff-act Revenue act of 1913: http://en.wikipedia.org/wiki/Revenue_Act_of_1913 http://law.enotes.com/major-acts-congress/federal-income-tax Internal Revenue Code of 1954: http://law.enotes.com/major-acts-congress/internal-revenue-act http://www.reference.com/browse/wiki/Internal_Revenue_Code_of_1954 http://en.wikipedia.org/wiki/Internal_Revenue_Code_of_1954 Tax reform act of 1986: http://www.answers.com/topic/tax-reform-act-of-1986 http://law.enotes.com/major-acts-congress/tax-reform-act http://en.wikipedia.org/wiki/Tax_Reform_Act_of_1986
4. the 16th amendment. ''The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration. ''