(1.) That in human covenants, in which things are promised on certain conditions, these conditions are supposed to be possible to be performed, otherwise the promise, depending thereon, is rendered void, and it contains no other than a virtual denial to make it good. Thus the king of Israel did not, at first, understand the message sent him by the king of Syria, requiring of him to heal Naaman of his leprosy, as a condition of peace and friendship between them; and the inference he makes from it was, that he had a design to seek a quarrel against him; and his reasoning would have been just, had it been intended in this sense, since the condition was not in his own power. Moreover, if a master should tell his servant, that he would give him a reward, in case he would perform the work of ten days in one, he would conclude nothing else from it, but that he was resolved not to give him any thing. Now, to apply this to our present purpose, we must consider whether faith, when it is a condition of the covenant of grace, be in our own power or no. There are some external acts thereof, indeed, which are so; but these are too low to be deemed conditions of salvation, or of the blessings of the covenant of grace; and as for those acts which are supernatural, or the effects of the exceeding greatness of the power of God, though they are inseparably connected with salvation, yet they are not in our power; so as that we may conclude, that they are proposed as conditions, in the same sense as those things are said to be, that are supposed to contain this ingredient in them.
In this respect, the covenant of grace, as to the conditionality of it, differs from the covenant of innocency, in which perfect obedience, which was the condition thereof, was so far in man’s power, that he could have performed it, without the superadded assistance of divine grace: but when, on the other hand, perfect obedience is considered, as a condition of fallen man’s _entering into life_, in which sense our Saviour’s reply to the young man’s question, in Matt. xix. 17. is understood by many, this is a plain intimation that eternal life is not to be obtained this way, inasmuch as the condition is impossible.