One way of approaching this question is to first ask "what would each verse have meant in the mind of the original author" taking account of who we believe was/were the human author's intended audience. When taking this approach, we must also take account of the genre of the writing.
In brief, Proverbs (at least until some of the later sections) are "of Solomon", intended for a general audience of both "naive" and the "wise man", intended to give wisdom to both:
1 The proverbs of Solomon the son of David, king of Israel:
2 To know wisdom and instruction,
To discern the sayings of understanding,
3 To receive instruction in wise behavior,
Righteousness, justice and equity;
4 To give prudence to the naive,
To the youth knowledge and discretion,
5 A wise man will hear and increase in learning,
And a man of understanding will acquire wise counsel,
6 To understand a proverb and a figure,
The words of the wise and their riddles. NASB
The book was written at a time when there was not a clear picture of exactly what 'eternal life' meant, to the author is very unlikely to have referring to life in that sense - rather a combination of
- preventing an early death through foolishness
- 'life' as in quality of life
eg Proverbs 3:2 :
2 For length of days and years of life
And peace they will add to you. NASB
or later in the same chapter:
22 So they will be life to your soul
And adornment to your neck. NASB
on the other hand, briefly speaking, John was writing into a very different context - to believers familiar with Jesus' teachings on the resurrection.
The meanings of the word 'life' in proverbs are including in and expanded upon by Jesus teaching, which includes a much clearer view of life with Him after 'death'.