How to share ethernet between MBP and iPad?
This is what you do:


Make sure the ethernet cable is plugged in, and that the MBP is using ethernet to connect to the internet
Open System Preferences and click on Sharing
Tick the checkbox that says "Internet Sharing"
From the drop down list, select Ethernet. Tick the WiFi (thanks Mateusz Szlosek) checkbox. It should look something like this: 
Click on Wifi Options, and configure your Internet Sharing network.
On your iPad, connect to the network you created.


Be sure to verify that internet sharing is actually enabled by making sure the checkbox is ticked! 

Instructions are taken from these 2 websites, so if I'm not clear, please visit here and here.