Who was faithful - see the note, Hebrews 2:17. He performed with fidelity all the functions entrusted to him.
To him that appointed him - Margin, “made.” The word “made,” however, is used in the sense of constituted, or appointed. The meaning is, that he was faithful to God. Perhaps Paul urges on them the necessity of considering “his fidelity” in order to keep “them” from the danger of apostasy. A leading object of this Epistle was to preserve those whom he had addressed from apostatizing from God amidst the temptations and trials to which they were exposed. In doing this, what could be a more powerful argument than to direct their attention to the unwavering constancy and fidelity of the Lord Jesus? The “importance” of such a virtue in the Saviour is manifest. It is seen everywhere; and all the great interests of the world depend on it. A husband should maintain inviolate fidelity toward a wife, and a wife toward her husband; a child should be faithful to a parent, a clerk and apprentice to his employer, a lawyer to his client, a physician to his patient, an ambassador to the government that commissions him.
No matter what may be the temptations in the way, in all these, and in all other relations, there should be inviolate fidelity. The welfare of the world depended on the faithfulness of the Lord Jesus. Had he failed in that, all would have been lost. His fidelity was worthy of the more attentive consideration from the numerous temptations which beset his path, and the attempts which were made to turn him aside from his devotedness to God. Amidst all the temptations of the adversary, and all the trials through which he passed, he never for a moment swerved from fidelity to the great trust which had been committed to his hands. What better example to preserve them from the temptations to apostasy could the apostle propose to the Christians whom he addressed? What, in these temptations and trials, could be more appropriate than for them to consider the example of the great apostle and high priest of their profession? What more proper for us now in the trials and temptations of our lives, than to keep that great and glorious example continually before our eyes?
As also Moses was faithful - Fidelity to God was remarkable in Moses. In all the provocations and rebellions of the Jews, he was firm and unwavering. This is affirmed of him in Numbers 12:7, to which place the apostle here alludes, “My servant, Moses, is not so, who is faithful in all his house.” The word “house,” as applied to Moses, is used probably in the sense of “family,” as it often is, and refers to the “family” over which he presided - that is, the Jewish nation. The whole Jewish people were a “household,” or the family of God, and Moses was appointed to preside over it, and was faithful in the functions of his office there.