Lightfoot, R. H. (edited by C.F. Evans) St. John's Gospel: A commentary with the text of the Revised version London: Oxford University Press, 1960, page 297.

    “This eternal life is defined as a growing knowledge . . .”

Morris, Leon. The Gospel According to John The International Commentary on the New Testament. Grand Rapids: William B. Eerdmans Publishing Company, 1971, page 719.

    “. . .  Jesus has in mind an ever increasing knowledge, not something given in its completeness once and for all.”

Tasker, R. V. G. The Gospel According to St. John: An Introduction and Commentary The Tyndale New Testament Commentaries. Grand Rapids: William B. Eerdmans Publishing Company, 1960, page 291

    “In the Greek the verb is in the present subjunctive, indicating that the ‘knowledge’ is a growing experience.”

Tenny, Merrill C. The Gospel of John In The Expositor’s Bible Commentary Vol. 9, Edited by Frank Gaebelein Grand Rapids: Zondervan Publishing House, 1981, page 162

    “. . .  eternal life . . . is endless, since the knowledge of God would require an eternity to develop fully . . .”