1 Corinthians 8:7

Howbeit there is not in all men that knowledge: but some, being used until now to the idol, eat as of. thing sacrificed to an idol; and their conscience being weak is defiled.

'that knowledge' -To me the best way to harmonize this verse with Paul's assertion in 1 Corinthians 8:1 'We all have knowledge'; is that all Christians intellectually believed verses 4-6, and yet all Christians hadn't been able to emotionally accept them.

'that even though all may believe at the theoretical level than an idol is no god, not all share this "knowledge" at the..emotional level.' (Fee p. 379)

'The Corinthians were like the superstitious among Christians today who shun the number 13, read their astrology charts, etc..while disclaiming belief in any supernatural power other than Jehovah.' (Willis p. 269)

'being used until now to the idol' -a convert from paganism, one that used to habitually engage in idolatry and idol feasts. One who was "brought up" in idol worship. 'It is the force of habit that still "grips" them when they eat such meat.' (Robertson p. 139)

'eat as of. thing sacrificed to an idol' -'Although they would admit the existence of only one God, they still ate the food offered to idols as an act of worship. Too, they considered anyone else who ate food sacrificed to idols to be doing the same thing.' (Willis p. 269)

'They still feel that eating such meat in some way connects. person with the idol..' (Lenski p. 342)

'their conscience being weak' -'is one that is not fully clear as to whether an act is right or wrong.' (Lenski p. 342)

'is defiled' -3435. moluno mol-oo'-no; probably from 3189; to soil (figuratively): -defile. This happens when they violate their conscience and choose to do what they believe is wrong. (Romans 14:23)

We should note that this verse infers that someone was "encouraging" them to eat and to eat against the convictions of conscience..'they must have been urged to eat else they wouldn't have done it.' (McGuiggan p. 125)