I've tabbed this because, like other Mumford songs, no-one else seems to have
got it anywhere near right. The tuning is Double Drop D, meaning you tune your
lowest and highest strings down from E to D, so low to high it's
(D/A/D/G/B/D). After watching live performances of this song this
tab is 100% correct, and straightforward.

The intro has you 'tapping' out these shapes with your thumb* and forefinger:

-------------------------------------------|
-------------------------------------------|
--9-----7-----11---------------------------|
--0-----0-----0----------------------------|
--x-----x-----x----------------------------|
--9*----7*----12*--------------------------|

The second time though you let the 7th fret shape ring out then strum UP
the guitar a D chord (000230) which then continues.

Then the verse chords are finger picked in typical Mumford style - the chords
are below, you can work out the pattern by ear:

D -  000230
A -  x02222
Bm - x24432
G -  5x0400

D (xx0232@1)       A (x02220@1)      Bm (x24432@1)                   A (x02220@1)         G (320003@1)      Bm"You (x24432@1)hold your truth so purely, but swerve not through the minds of men..
              A..this (x02220@1)lie is dead"

This pattern continues, before it then goes back to the intro bit. Then, the
chorus uses the same chord shapes shown previously but now you're strumming:

G (320003@1)             D (xx0232@1)           A (x02220@1)                     DWhispers (xx0232@1)in the dark, steal a kiss and you'll break a heart
             G (320003@1)                   D (xx0232@1)              A (x02220@1)              DPick (xx0232@1)up your clothes and curl your toes, learn your lesson, leave me whole
         G (320003@1)           D (xx0232@1)            A (x02220@1)     DSpare (xx0232@1)my shins for the ark, I was too slow to depart
      G (320003@1)               D (xx0232@1)            A (x02220@1)              DI'm (xx0232@1)a cad but I'm not a fraud, I'd set out to serve the lord
A (x02220@1)       D (xx0232@1)        G (320003@1)               D...And (xx0232@1)my heart, was colder when you'd gone
A (x02220@1)              D (xx0232@1)       G (320003@1)                  D...And (xx0232@1)I lost my head, but found the one that I loved

Then the "Under this sun" part uses these shapes:

--0---0----0---0---0--0----|
--0---0----0---0---0--3----|
--9---11---9---11--6--2----|
--0---0----0---0---0--0----|
--x---x----x---x---x--0----|
--9---12---9---12--7--0----|

Then you play the intro part again but now you're strumming / palm muting
and you play it 4 times. At the end of the 2nd repeat you go down to the D
chord, and at the end of the 3rd repeat there's a slight variation
on the shape around the 12th fret that's easy to work out.

Finally then you're back to the same chorus chords followed by the shapes
at the end, same as the "Under this sun" bit.

Done!