A crest forms part of heraldic arms granted by the Lord Lyon in Edinburgh. A crest was never granted to a family, but only to an individual. Once granted, arms are inherited eldest son to eldest son. Younger sons and daughters can use the crest in their own arms, but must display them "differenced" ; i.e., must include some different element or depiction to distinguish the new arms from the heritable arms of the head of the family line. Hence, the head of a branch of a major family line (cadet line) may have a crest that looks similar to that of the head of the major line, but use a different motto, coloration, device, or additional piece of art work.
The crest with the hand and the dagger tip tilted to the right forms part of the arms granted to the eldest sons in the Towie Barclay lineage. The hand holding a dagger proper (both the hand and the dagger depicted in their natural coloration) rises out of a chapeau azure (blue hat) whose trim is ermine fur. The motto of the Barclays of Towie is "Aut agere aut mori", translated as "Either action or death", or more simply as "Action or Death". This crest, when placed within a strap and buckle is the crest used by Clan Barclay International, as the Chief of Clan Barclay is Peter C. Barclay, Towie XXXI, of London. This line is historically older than other lines including the Urie Barclays of Kincardineshire.
The crest that includes the hand with a dagger erect or sometimes a sword erect is affiliated with bearers of arms in the Collairnie family (Fife), with the Barclays of Touch, Pearston, Ladyland and Paisley (the latter three families were located in the Ayrshire or Renfrewshire areas of western Scotland). The Collairnie crestdepicts a hand with a sword erect proper, hilted and pommelled or (gold). The Collairnie motto is "Crux Christi Solamen". The Barclay of Touch crest is the same as the Collairnie with a motto reading "Crux Salutem Confert" and the Pearston Barclay crest is again the same with a motto reading "Crux Christi Nostra Corona", or "Christ's Cross Our Crown".
There are other Barclay cadet lines that have other crests using elements other than the hand with sword or dagger, depending upon the grant of arms from the Lord Lyon.