What would you do if you were approached by a messenger of God who ordered you to gouge out your own eyeballs?

What Jesus was saying was that you need to get rid of the things in life that lead you to sin. There are few if any circumstances that would require you to literally maim yourself in order to avoid sinning. Rather, you can take a less severe route. For example, if you have an issue with pornography, you can place your computer in a public area of the house (as opposed to your bedroom, for example) or cut off your internet access altogether.