There are many things that prevent good digestion of the Word:
We sometimes immediately think of someone else who should hear and apply this to their life, thereby hardening our own heart.
We sometimes become instantly defensive and feel attacked thereby creating great stress and producing indigestion.
We may fill up on junk food leaving little room or appetite for real food that truly satisfies.
We may dwell excessively on our fears, regrets, pain, resentments, guilt etc. leaving no time or willingness or desire for saving truth.
Enzymes aid in digesting food in the stomach. What are spiritual enzymes that can assist us in better digesting the Word so we don't get a sour stomach like John? (Rev. 10:9,10)