And was the day of my delight As pure and perfect as I say? The very source and fount of Day Is dash'd with wandering isles of night.
If all was good and fair we met, This earth had been the Paradise It never look'd to human eyes Since our first Sun arose and set.
And is it that the haze of grief Makes former gladness loom so great? The lowness of the present state, That sets the past in this relief?
Or that the past will always win A glory from its being far; And orb into the perfect star We saw not, when we moved therein?
Tennyson wonders now if his memories of the two of them are accurate. Were things really that good?
He affirms that they are, because now his world is like shadows have stolen the very sun away. That's pretty bad, gang.
Their friendship was so good (all together now: how…good…was it?) that Earth was pretty much a Paradise (and we're talking Biblical, so this is big) and had never been looked at by people in this way before—since the beginning of time, even.
He again questions if he's reading things correctly, and thinks that his perception might be affected by the "haze of grief" he is experiencing, which could make things seem better than they actually were.
Or, it could be that distance always make events from the past seem better than they really were. (And trust us—this is true. You'll start getting all nostalgic, even for the Beebs, sometime when you hit age 30.)
And he gives us a nice image to play with in this regard. Looking at this in the past is like seeing a perfect star from far away that you didn't even notice when you were close up.