<p>4:5 <i>For it is sanctified through the word of God and prayer</i>- Peter had been taught that it was the Lord's sacrifice which sanctified unclean food. So &quot;the word of God&quot; may refer, as it often does, to the Lord Jesus rather than the Bible. For the Bible in that sense doesn't cleanse unclean food. It could also refer to 'the Gospel'. Or it could be that Paul had in mind the simple statements of Genesis, that we have been given all food by God (Gen. 1:29; 9:3). This would be typical of Paul- as he does so powerfully in Galatians, he bids us return to God's original intentions in Genesis and consider the Mosaic Law as a temporary addition which has now ended. Food is not of itself sanctified or not sanctified (Rom. 14:14), so I doubt that Paul meant that the chips on your table are made somehow holy because you prayed over them. It is human life which can be sanctified to God, as Paul so often says in his letters. Thanksgiving for food is therefore a recognition that we have been given food in order to live life which must be sanctified to Him.</p>