Jesus’ Obedience to the Law as a Covenant of Works

To understand the distinction between believers’ relation to the covenant of works and the covenant of grace it is necessary to first grasp Jesus’ relation to both. The following quote from Herman Bavinck explains well the former aspect of this question–how the Christ relates to the covenant of works:

Even more, as a human being Christ was certainly subject to the law of God as the rule of life; even believers are never exempted from the law in that sense. But Christ related himself to the law in still a very different way, namely, as the law of the covenant of works. Adam was not only obligated to keep the law but was confronted in the covenant of works with that law as the way to eternal life, a life he did not yet possess. But Christ, in virtue of his union with the divine nature, already had this eternal and blessed life. This life he voluntarily relinquished. He submitted himself to the law of the covenant of works as the way to eternal life for himself and his own.

The obedience that Christ accorded to the law, therefore, was totally voluntary. Not his death alone, as Anselm said, but his entire life was an act of self-denial, a self-offering presented by him as head in the place of his own. (Herman Bavinck, Reformed Dogmatics, III: 379; emphases mine.)