Commentaries:
Unless we eat His flesh (represented by the unleavened bread of the Passover ritual) and drink His blood (symbolized by the wine), we have no life in us and will not inherit eternal life! It is vital, therefore, for all converted Christians to observe the New Testament Passover every year.
Earl L. Henn
Holy Days: Passover
Verses 47-51 reinforce the strategic role eating—listening to and believing in—God's living Word, Jesus Christ, plays in producing everlasting life. The knowledge that one gains by listening to and applying God's Word results in the greatest of all possible blessings: everlasting life. Remember, eternal life is quality of life as God lives it, as well as endless life.
Notice also that those who believe already have this life. It is the gift of Jesus Christ. Those who have believed have "eaten" Him, and thus He calls Himself the Bread of Life. This Bread does what no other bread, even manna, can do. It works to impart spiritual life and banish spiritual death. He adds that He is the "living bread," implying that He lived in the past, is living in the present, and will live in the future. He will always be there to provide nourishment. Further, we must not just taste this Bread. Once the process begins, we must eat it continuously so that we can assimilate Him into us and begin living life in Him and He in us.
Up to this point, Jesus has insisted that He, not manna, is the true Bread of Life. Now, He adds a new thought: This Bread will give His life in the flesh so the world may also live. He means that we cannot have everlasting life without also "eating," believing, accepting, assimilating, His voluntary, vicarious death by crucifixion for us. The Father gives the Son, and the Son gives Himself. Apart from this sacrifice, Christ ceases to be bread for us in any sense.
John W. Ritenbaugh
Eating: How Good It Is! (Part Four)
Other Forerunner Commentary entries containing John 6:48:
John 3:1-12