The resistance of your skin could be larger than 100k?.
It mean that for 10A to flow through your body, the voltage need to be larger than 100kV.
Normally, you only have 110/220V at home.
However, 1-10mA could cause your heart beat to stop. The resistance could be reduced to 10k? If you hand is wet. So it is dangerous to touch the hot wire.
Voltage is the potential difference between two reference point.
The earth provide a ground reference potential. The current could also formed due to capacitor coupling (which you might not have learned).