Commentaries:
"Foods" represent physical, ritual observances. God is the author of rituals as well, and they have their place. Paul is referring to the ritual observances, the ceremonies, of the Old Covenant, as food was involved with them. But over the years, people came to have a superstitious attitude toward such things—that if, for instance, they ate of something that had been offered in sacrifice, it would impart to them some spiritual strength. Of course, it could not. We receive spiritual strength from spiritual things.
John W. Ritenbaugh
Grace Upon Grace
Other Forerunner Commentary entries containing Hebrews 13:9:
Matthew 9:14-17
Matthew 12:38-40
Matthew 16:4
Mark 2:18-22
Luke 5:33-39
Luke 11:29-30