Hebrews 3:5

ἐν ὅλῳ τῷ οἴκῳ αὐτοῦ, i.e. in all God’s house. Two “houses” are contemplated, Mosaism and Christianity, the Law and the Gospel. Both were established by God. In the household of the Law, Moses was the faithful minister; in the household of the Gospel, Christ took on Him, indeed, “the form of a slave,” and as such was faithful even unto death, but yet was Son over the House. This seems a more natural explanation than that the writer regards both the covenants as one Household, in which Moses was a servant, and over which Christ was a Son.

θεράπων, “voluntary attendant.” The word used is not δοῦλος “slave,” nor διάκονος “minister.” It is also applied to Moses in the Ep. of Barnabas and in Exodus 14:31 (LXX.).

τῶν λαληθησομένων. The fut. pass. part. is rare in the N. T. The things were to be spoken afterwards by Christ, the Prophet to whom Moses had pointed, Deuteronomy 18:15. The Law and the Prophets did but witness to the righteousness of God which was to be fully revealed in Christ (Romans 3:21). They were but a shadow of the coming reality (Hebrews 10:1). But although it is natural to understand the expression in this way, the author possibly meant no more than that the faithfulness of Moses was an attestation of the Law which was about to be delivered. If he had directly meant that Moses witnessed to the Gospel he would perhaps have written τῶν μελλόντων λαλεῖσθαι.