Robert Traill (Stedfast Adherence to the Profession of our Faith), Works 3:129:
There is this in the covenant, that the promisor and fulfiller is the same. God does not entrust the fulfilling of his promises to any body else; we are not to take God’s promise as a bill, and call upon another man to pay it: no, we are to bring them all to himself, he is the fulfiller. What a blessed saying is that of good Hezekiah, Isa. 38:15, What shall I say? He hath both spoken unto me, and himself hath done it? I got the word from him, and I got the deed from him; the words were the words of his mouth, and the deeds were the work of his hands: He hath both spoken unto me, and himself hath done it. Here is a remarkable emphasis: a spiritual eyeing that this godly man had of the eminent hand of God in fulfilling his gracious word to him.
There is this in the covenant, that the promisor and fulfiller is the same. God does not entrust the fulfilling of his promises to any body else; we are not to take God’s promise as a bill, and call upon another man to pay it: no, we are to bring them all to himself, he is the fulfiller. What a blessed saying is that of good Hezekiah, Isa. 38:15, What shall I say? He hath both spoken unto me, and himself hath done it? I got the word from him, and I got the deed from him; the words were the words of his mouth, and the deeds were the work of his hands: He hath both spoken unto me, and himself hath done it. Here is a remarkable emphasis: a spiritual eyeing that this godly man had of the eminent hand of God in fulfilling his gracious word to him.