Whereas in the middle ages the concept of duthchas held precedence, the balance was tilting in favour of the concept of oighreachd in the early modern period. This shifting balance reflected the continuing importance of Scots Law in shaping the structure of clanship. In addition to the award of charters to the fine, continuity of heritable succession was secured by the acceptance of primogeniture. The 'tainistear', the heir to the chief, was usually the direct male heir and although attention has tended to focus on those clans where the direct heir was set aside in favour of a more politically accomplished or belligerent relative, disputes over succession were not characteristic of the Highlands beyond the sixteenth century; indeed, by the seventeenth century, not only was the setting aside of primogeniture a rarity, but male succession over several generations was increasingly governed and restricted by the law of Entail which prevented the division of landed estates among female heirs and thus the loss and alienation of clan territories.
The legal process primarily used to settle criminal and civil disputes within clans was that of arbitration. Within the clan, the offending and aggrieved parties put their respective case to an arbitration panel drawn from their leading gentry and over which their chief presided. In disputes between clans, the chiefs served as the procurators (legal agents) for the offending or aggrieved parties before an arbitration panel drawn from equal numbers of leading gentry from each clan and presided over by a neighbouring chief or landlord. The decision of the arbitration panel, from which there was no appeal, was recorded in the most convenient Royal or Burgh court. Arbitration was based on reparations, known as assythment, rather than retribution. The compensation awarded to the aggrieved party took account of such variables as the age, status and family responsibilities of the victim, as well as the nature of the crime. On payment of reparation the offending party was indemnified against any further action for redress. The process depended ultimately on the willingness of clans to make prompt reparation, a situation made more likely by the regular contracting of bands of friendship between clans which made standing provision for arbitration. Again, these bands had the force of law and were recorded in the most convenient Royal or Burgh court.

The most important forms of social bonding in the clans, in addition to legal bands, were fosterage and manrent. The marriage alliance, which reinforced links with neighbouring clans as well as kinship within territorially diverse families, was also a commercial contract involving the exchange of livestock, money and land through payments which in the case of the bride was known as the 'tocher' and for the groom, the `dowry'. The gentry of the clan were expected to underwrite the contracts made by their chiefs or leading lairds, a legal obligation which grew in importance as increasing numbers of marriage contracts were made outwith Gaeldom in the course of the seventeenth century. Marriage ties, even when forms of trial marriage such as handfasting had been repressed in the wake of the Reformation, were the least durable aspect of social bonding. Conversely, fosterage, the bringing up of the chiefs children by favoured members of the leading clan gentry and in turn, their children by other favoured members of the clan, cemented ties of such intensity that it was not regarded as exceptional for foster-brothers to sacrifice themselves in protecting their chiefs. The commercial facet of this relationship reinforced feelings of clan cohesion in making particular provision, usually in the form of livestock, for foster-children on their reaching adulthood or on the death of their foster-parents.
The third form of social tie was manrent. This was a bond contracted by the heads of satellite families who did not live on the estates of the clan elite, but to whom they affiliated to ensure territorial protection. Bonds of manrent were reinforced by calps, the payment of death duties. On the death of these satellite heads, their families usually paid their best cow or horse to the chief in recognition of his protection and as a mark of personal allegiance. Although calps were banned as oppressive by Parliament in 1617, the need for protection could not be proscribed by legislation and manrent continued covertly. While manrenting was apparently less frequent, bands were made less to create new ties of dependency then to renew protection after a lapse of a generation, and notably after the political divisions occasioned by civil wars in 1644-47 and 1689-90.