Wow, 131 posts and no Clan Keith. Am I the only one??
According to the Keith Society web site their are two recognized mottos for Keith:

Veritas vincit (truth conquers)

Quae amissa salva (what has been lost is safe)- referencing the role that the Keith family played in protecting the Scottish Regalia (crown, scepter, sword and scabbard) from Oliver Cromwell's troops during 1651-2