The sure mercies of David, or, A second part of heart-treasure : wherein is contained the summ and substance of Gospel-mercies purchased by Christ and promised in the Covenant of grace : together with the several ways how they are made sure to all the heirs of promise and how they are to be improved for the saints fort and defence, settlement and incouragement in shaking and back-sliding times : being the fruit of some meditations upon Isa. 55,3 /