“Who has not found the Heaven — below —
Will fail of it above”

Book of Taliesin (c. 1275?), The Elegy of the Thousand Sons
Context: The number that have been, and will be,
Above heaven, below heaven, how many there are.
And as many as have believed in revelation,
Believed through the will of the Lord.
As many as are on wrath through the circles,
Have mercy, God, on thy kindred.
May I be meek, the turbulent Ruler,
May I not endure, before I am without motion.
Grievously complaineth every lost one,
Hastily claimeth every needy one.

Canto III, stanza 2.
The Lay of the Last Minstrel (1805)
Context: In peace, Love tunes the shepherd's reed;
In war, he mounts the warrior's steed;
In halls, in gay attire is seen;
In hamlets, dances on the green.
Love rules the court, the camp, the grove,
And men below, and saints above;
For love is heaven, and heaven is love.

"Little Things" (1845) as quoted in Our Woman Workers: Biographical Sketches of Women Eminent in the Universalist Church for Literary, Philanthropic and Christian Work (1881) by E. R. Hanson. These were the final words of the poem in the original publication, but later versions published anonymously by other authors appended various additions to this. It has also often appeared credited to Carney in a variant form:
Little deeds of kindness,
Little words of love,
Help to make earth happy
Like the heaven above.

No. I, The Vagabond, st. 4.
Songs of Travel and Other Verses (1896)

Book I, Ode II, No. 1: "For the Winter Solstice", stanza v, lines 48–50
Odes on Several Subjects (1745)

Manmadin, The Indian Cupid. Floating down the Ganges from The London Literary Gazette (14th December 1822) Fragments in Rhyme VII
The Improvisatrice (1824)

Time and Eternity, p. 234
Collected Poems (1993)

Gakumon no Susume [An Encouragement of Learning] (1872–1876).

Essay 3, Aphorism 10
On the Genealogy of Morality (1887)
Variant: Whoever, at any time, has undertaken to build a new heaven has found the strength for it in his own hell...