A.T. Robertson Commentary Acts 7:38

"This is he that was in the church in the wilderness with the angel that spake to him in the Mount Sinai, and with our fathers: who received living oracles to give unto us:" — Acts 7:38 (ASV)

In the church in the wilderness (εν τη εκκλησια εν τη ερημω). Better rendered "congregation" here as in Heb 2:12 (Psalms 22:22), the people of Israel gathered at Mt. Sinai, the whole nation. Moses is here represented as receiving the law from an angel as in Heb 2:2; Galatians 3:19 (Deuteronomy 33:2, LXX) and so was a mediator (μεσιτης) or middle man between the angel and the people whereas Jesus is the Mediator of a better covenant (Hebrews 8:6). But Exodus does not speak of an angel.

Living oracles (λογια ζωντα). A λογιον is a little word (diminutive of λογος). Common in the old Greek, LXX, Philo, in ecclesiastical writers for sayings of Christ, Papias (for instance) saying that Matthew wrote in Hebrew (Aramaic) "Logia of Jesus." Oxyrhynchus papyri fragments called "Logia of Jesus" are of much interest though only fragments. The Greeks used it of the "oracles" or brief sayings from Delphi. In the N.T. the word occurs only four times (Acts 7:38; Romans 3:2; Hebrews 5:12; 1 Peter 4:11). Here the participle ζωντα, living, is the same used by Peter (1 Peter 2:4f.), stone (λιθος) of Christ and Christians. The words from God to Moses are still "living" today. In 1 Peter 4:11 the word is applied to one who speaks λογια θεου (oracles of God). In Ro 3:2 Paul refers to the substance of the law and of prophecy. In Heb 5:12 the writer means the substance of the Christian religious teaching.