This is given in The Worshiping Church (Hope Pub., 1990) as "traditional English carol, c. 18th C.". It's not in the New Oxford Book of Carols, and I don't have my old OBC at hand to check it. The tune is usually called "Jacob's Ladder", although that invites confusion with the American spiritual, with which it has nothing in common, so I prefer to call it "Ladder of Mercy".

As Jacob with travel was weary one day
Anonymous English carol

As Jacob with travel was weary one day,
at night on a stone for a pillow he lay;
he saw in a vision a ladder so high,
that its foot was on earth and its top in the sky:

     Refrain:
Alleluia to Jesus, who did on the tree
and has raised up a ladder of mercy for me,
and has raised up a ladder of mercy for me.

The ladder is long, it is strong and well-made,
has stood hundreds of years and is not yet decayed;
many millions have climbed it and reached Zion's hill,
many millions by faith now are climbing it still.

Come, let us ascend! All may climb it who will,
for the angels of Jacob are guarding it still;
and remember, each step that by faith we pass o'er,
many prophets and martyrs have trod it before:

And when we arrive at the haven of rest,
we shall hear the glad words, "Come to me, all the blest,
here are regions of light, here are mansions of bliss."
Who would not want to climb such a ladder as this?

I see no sign of it in the DT, but it's called traditional or anonymous wherever I've found it.

Haruo