_Anno_ 1640, when the king had, by the advice of the clergy, caused burn the articles of the former treaty with the Scots, and again prepared to chastise them with a royal army, the Scots, resolving not always to play after-game, raised an army, invaded England, routed about 4000 English at Newburn, had Newcastle surrendered to them, and within two days, were masters of Durham; which produced a new treaty, more favourable to them than the former; and with this army was Mr. Blair, who went with lord Lindsay's regiment; and, when that treaty was on foot, the committee of estates and the army sent him up to assist the commissioners with his best advice. Again after the rebellion in Ireland 1641, those who survived the storm, supplicated the general assembly 1642, for a supply of ministers, when severals went over, and among the first Mr. Blair. During his stay there, he generally preached once every day, and twice on Sabbath, and frequently in the field, the auditors being so large, and in some of these he administered the Lord's supper. After his return, the condition of the church and state was various during the years 1643, and 1644; and particularly in Aug. 1643, the committee of the general assembly, whereof Mr. Blair was one, with John earl of Rutland, and other Scots commissioners from the parliament of England, and Messrs. Stephen Marshal and Philip Nye, ministers, agreed to a solemn league and covenant betwixt the two kingdoms of Scotland and England; and in the end of the same year, when the Scots assisted the English parliament, Mr. Blair was, by the commission of the general assembly, appointed minister to the earl of Crawford's regiment; with whom he stayed until the king was routed at Marston-muir July 1644, when he returned to his charge at St. Andrews. The parliament and commission of the kirk sat at Perth in July 1645. The parliament was opened with a sermon by Mr. Blair; and, after he had, upon the forenoon of the 27th, a day of solemn humiliation preached again to the parliament, he rode out to the army, then encamped at Torgondermy, and preached to Crawford's and Maitland's regiments, to the first of whom he had been chaplain:--He told the brigade, That he was informed that many of them were turned dissolute and profane, and assured them, that though the Lord had covered their heads in the day of battle (few of them being killed at Marston-muir), they should not be able to stand before a less formidable foe, unless they repented. Though this freedom was taken in good part from one who wished them well, yet was too little laid to heart; and the most part of Crawford's regiment were cut off at Kilsyth in three weeks afterwards.