Rejoice in the Lord, ye righteous,.... In the word of the Lord, as the Targum; in Christ, the essential Word, in his person, the greatness, glory, and fulness of it; in his righteousness, and in salvation by him, and that always; see Php 4:4,and give thanks at the remembrance of his holiness; of his essential holiness, as a divine Person, in which he is glorious, and which appears in all that he has done; and of the holiness of his nature and life, as man and Mediator, which are imputed to his people for their justification; and at the remembrance of that holiness which they have from him, and are made partakers of in sanctification: and at the remembrance of that perfect holiness which they shall have with him in heaven to all eternity.
Holiness may also signify his faithfulness in the discharge of his work and office as Mediator, and in the fulfilment of his promises to his people; See Gill on "Ps 30:4".