He entered the Congregational ministry and held pastorates at Bathgate, West Lothian and at Aberdeen.
On his father's death he had been offered a living by a relative, Sir Alexander Burnet, and in 1863 the living of Saltoun, East Lothian, had been kept open for him by one of his father's friends.
(For early history see Lothian; Northumbria; Strathclyde.) In the 12th century were founded the abbeys of Hexham and Alnwick, the priory church of Lindisfarne and the cathedral of Carlisle on the English side, and on the Scottish the abbeys of Jedburgh, Kelso, Melrose and Dryburgh.
Yet even under such conditions Bruce had to retire to the mountains, and to allow the invaders to range unopposed through Lothian and Fife, and even beyond the Tay.
Unfortunately for himself he made the mistake of requiring too much from Baliolforcing him to cede Lothian, Tweeddale and the larger part of Galloway, and to promise a tribute.