The Idea in Brief
The Masoretic Text for this passage contains marginalia written in Palestinian Aramaic which will cue the reader to understand the verse according to how the Masoretic scholars understood the text. Based on this marginalia, the following translation is how the Masoretic scholars understood this verse.
6 [The example of] Enoch for a child according to his way [i.e., the way of Enoch]; even when he is old (like Methuselah) he will not depart from it.
These marginalia comments imply that (1) “the way of Enoch” is the holy walk of Enoch with God first mentioned in Gen 5:24, and (2) the example here is Methuselah, the child of Enoch, who was righteous and therefore had lived very long.
The idea then would be to bring the child to walk and meet the Lord in personal experience (“the way of Enoch”) in order that the child will mature and persevere in righteousness.
The personal noun “Enoch” appears sixteen times in the Masoretic Text of the Hebrew Bible. In all but one instance, the word appears with the Hebrew holem waw, which is a vowel helper, or mater lectionis. That is, in Gen 25:4 the personal noun “Enoch” appears without the mater lectionis, and there is a note in the margin of the Masoretic Text that indicates three instances in the Hebrew Bible where the word appears without the holem waw: Gen 25:4; Nu 26:5; and Prov 22:6. The margin note appears to the left of the verse containing the word in question. At the foot of the leaf in the Codex appears the corresponding footnote. This footnote references the three verses. In other words, the Masoretic scholars are making the conclusion that in each of these three verses the references are made to either the personal noun “Enoch” or to the "Hanochites" ("Enoch" in Nu 26:5 contains the holem waw but "Hanochites" in the same verse does not). We know that because in the footnote is the phrase in Aramaic (חנך ג̇ חס̇ בליש), which means the word חנך appears three times defectively in this usage.
Most, if not all, Bible scholars believe that the fist word in Prov 22:6 is the Qal imperative second personal singular of the Hebrew verb חָנַךְ, and therefore has nothing to do with “Enoch.” However, according to Gesenius, within the Hebrew Bible, Hebrew infinitives, imperatives, and imperfects in the Qal are written defectively (without the vowel helper) with rare exceptions. In other words, the Masoretic scholars did not see the first word in this verse as the defective spelling of the qal imperative of the verb חָנַךְ, which would be a superfluous observation, but the defective spelling of the personal noun “Enoch,” which lacks the holem waw. The Masoretic scholars reinforce their approach with more examples.
For example, in Prov 22:6, there is the following comment in the margin of the Masoretic Text with regard to the first word of the verse, חֲנֹךְ. In this regard, the comment in the margin states: “ב̇ ראש פסוק מתושלח,” which means, “In two instances the word begins a verse, Methuselah. Please see the ACTUAL screenshot below from Page 838 of the PDF version of the Codex Leningrad online.
In other words, the Masoretic scholars (who lived, breathed, memorized, and recited the Hebrew Bible) saw the father of Methuselah in this verse. When we use Bible software to search for the other place that “Enoch” begins a verse in the Bible, we discover that the other place where the word begins a verse is 1 Chr 1:3, which is in reference to the “Enoch” from the Book of Genesis, Chapter 5. The margin notes for that verse make no mention of “Methuselah” because the verse already states in the verse that “Enoch” is the father of “Methuselah.”
In conclusion, the Masoretic scholars used their margin notes for several purposes, and in some instances (as this discussion explained) there are small nuggets of gold. According to the late Bible scholar Israel Yeivin (1980), the Masoretic editors did not use their margin notes for superfluous purposes, nor did they mix and match the variant spellings of verbs and nouns, but only those variants unique to one particular word or words. Thus the observation of the various comments of the Masoretic scholars through their marginalia notes are not the mixing and matching of the word “Enoch” with Hebrew verbs that are spelled with the same letters with or without the holem waw. (They were not annotating variants of the holem waw in the Qal imperative, which was superfluous in the Hebrew Bible according to Gesenius.) Instead the Masoretic scholars were focused on the personal noun “Enoch” (father of Methuselah) in Prov 22:6, for which they were indicating specific variants of the same specific personal noun within the Hebrew Bible.
In summary, while the plain and normal reading of Prov 22:6 will suggest to most modern readers of Biblical Hebrew the qal imperative form of the Hebrew verb חָנַךְ would be in view, the Masoretic scholars chose instead to understand the first word of this verse to be in reference to the personal pronoun Enoch, the father of Methuselah. To ensure no misunderstandings, the Masoretic scholars included the actual word “Methuselah” in the margin notes (the so-called Masorah Parva) in order to ensure that the readers understood the Masoretic understanding of the passage. That is, the main thrust of the idea would be to bring the child to have personal first-hand experience walking with the Lord (that is, “the way of Enoch”) in order that the child will mature and persevere in righteousness as he gets older (for which we have the example of the long-lived and righteous Methuselah, the son of Enoch, from the Book of Genesis).
Yeivin, Israel (1980). Introduction to the Tiberian Masorah (trans. by E.J. Revell). Stuttgart: Society of Biblical Literature, passim.