
The crest of the chief of Guthrie is an arm holding a sword,
with the motto ‘Sto pro veritate’.
Guthrie of that Ilk does not appear in Nisbet’s System of
Heraldry of the 1720s, indicating that they hadn’t got their arms registered by
that time. Sir Henry Guthrie of Kingsedward had, however, although his crest
was a lion’s paw holding a palm tree, but he at least has the Sto Pro Veritate
motto. Although the Guthries clearly had arms at this time, it’s unclear when
the chief adopted crest and motto. Either Sir Henry was following the chief, or
else the chiefs later adopted his Sir Henry’s motto. 
The first we find the crest recorded is in 1817 in Alexander
Deuchar’s British Crests: containing the crests and mottos of the families of
Great Britain and Ireland.
The sword may be a reference to Sir David Guthrie of that
Ilk’s service as Armour Bearer and Captain of the King’s Guard for James II,
although it may just be a standard statement of military prowess.
The motto Sto pro Veritate, which translates as ‘I stand for the Truth’ has a religious overtone, which likely refers to the Guthrie’s support of the Reformation, which led them to take the infant James VI’s side in the civil war against Mary Queen of Scots in the 1560s and 1570s.