days and years

Today, I was caught in the crossfire of Isaiah 63, getting stuck around vv 4 - 7. The introduction to the chapter is [i]rich[/i].

Then, I noticed v 4 again, particularly 'day' and 'year'.

In the light of many Christians being readily (and perhaps not critically enough), amenable to extract [u]literal[/u] meanings from [i]other[/i] mentions in scripture of days, weeks and years - when it suits some doctrine they have heard - I wondered what is the [u]biblical[/u] meaning of [u]day[/u] and [u]year[/u], in the way Isaiah himself uses them.

Here is a control verse: Ephesians 5:9 (It is in parenthesis in the text.)

(For the fruit of the Spirit [is] in all goodness and righteousness and truth;)

Here, we see clearly that 'goodness', 'righteousness' and 'truth', being used all in the same verse, must have each their own biblical meaning. Truth, for instance, is not something one tells in court, it is Jesus Christ.

Going back to 'day' and 'year': as in 'the last day', or 'in the year that', either these words mean something slightly different depending on their context, or, they mean twenty-four hours, and three hundred and sixty-five days every time.

If it's not the latter, what are they?

4 For the [u]day[/u] of vengeance [is] in mine heart, and the [u]year[/u] of my redeemed is come.

The 'year' appears to refer to the future; yet, coming from the [i]heart[/i] of the I AM comes from the [i]mouth[/i] of the prophet in the [u]present[/u] tense

Did the 'day of vengeance' occur before the cross? If so, when?

I have the same question about 'the year of my redeemed'. If so, when?