To testify against error and its consequences. Heathenism it is necessary to denounce according to the word of Divine truth. It is desirable to condemn it, as originating in the corruption of true religion, making progress by assimilating to itself the corruptions of the human heart under the influence of satan, and tending towards the ruin of the soul. The manner in which it is described in the sacred volume, and represented there as certainly to be dissipated, should be made known by those who come in contact with it. And the glorious truth of God, in contrast with it in its character and tendencies, should be displayed. In like manner, should infidelity--whether Jewish or Gentile, Mahommedanism and Socinianism on the one hand, and Popery and Prelacy on the other, and every other false system, be dealt with. To assault such by the exhibition of the truth of God, and to vow to do so, his people have every warrant and encouragement. They fear him, and under his banner as his Covenanted servants, are called to the duty. "Thou hast given a banner to them that feared thee, that it may be displayed because of the truth."[312] Hence, in conclusion, First, Covenanting should engage all to every former good attainment. The obligation of a permanent duty cannot be dissolved; but the observance of it may and ought to be vowed successively. For a reason, the same as, or similar to, that for which it was vowed at first, it may, on some occasions, be promised by vow and oath again. The Divine law holds every moral being bound to duty; yet it admits, nay, commands, the making of promises in Covenanting to do it. As the original command to obey, does not render the vow unnecessary, so neither does one vow remove the necessity for another. It is in vain to object, that as the vow or oath of marriage need not be repeated by the parties, so neither need any other. Though on account of the esteemed and real solemnity of that original covenant, it is not requisite that it should be renewed in the formal manner in which it was made at first, it is, nevertheless, manifest from Scripture, inculcating the use of the vow, that the parties may thereafter vow to God to continue to fulfil their first engagements. Were one duty that was formerly obligatory not to be engaged to in Covenanting, then might none other. Hence, only duties becoming incumbent at present could be vowed, and accordingly, as all the duties of the moral law were incumbent before, none of these could be vowed at all, and therefore, in no circumstances whatever, could the vow be made. The absurdity of the conclusion is sufficiently manifest. We are warranted to maintain that what was Covenanted before, no less than it should be performed, should be vowed again. "Nevertheless, whereto we have already attained, let us walk by the same rule, let us mind the same thing."[313]