# Do not be yoked together with unbelievers

"Only be yoked together with believers" 

# be yoked together with unbelievers

"team up with" or "have a close relationship with". Paul speaks of working together toward a common purpose as if it were two animals tied together to pull a plow or cart.

# For what association does righteousness have with lawlessness?

"For righteousness can have no association with lawlessness." 

# For what fellowship does light have with darkness?

"Light can have no fellowship with darkness.". The words "light" and "darkness" refer to the moral and spiritual qualities of believers and unbelievers.