In 1638, events in his native country again compelled him to return to Scotland, where he was appointed "Lord General" in command of the Army of the Covenant by the Scottish administration, and as such participated in the Bishops' Wars. Scottish regiments were generally called into service by the lairds and clan chieftains obliging their tenants with feudal duty or coercion to send their kin into battle. However, support among the Presbyterians of Scotland was widespread and the Covenanters' army swelled to over 20,000 men. From 1639 they rallied under a flag bearing the motto "For Christ's Crown and Covenant". Most of the officers of the Army of the Covenant were veterans of Swedish service brought home from the continental wars to form Scotland's first professional army. This took place after careful negotiations in the Swedish Riksråd (state council) during which Leslie worked behind the scenes to ensure Chancellor Axel Oxenstierna allowed up to 300 officers to be decommissioned along with an unknown number of ordinary soldiers. He was also able to bring from Sweden his arrears of pay in the form of cannon and muskets as "parting gifts" and these were transported for him on Swedish naval vessels. The payment arrangement meant that the Swedes could claim that they were not supporting rebellion in Scotland, only paying off a debt.