Answer to the riddle asked a few days ago, “Why is the Law called ‘the gospel’ in Hebrews 4:2?”
The ‘good news’ at Sinai was that God was going to live with His people, and the Law was part of it. In other words, the church at Sinai had the good news of ‘God with us’ preached to them just as we have.
The Law was to facilitate ‘God with us,’ a.k.a. the gospel. God, in His grace, was taking up residence, and following the Law was (and is) a loving response (faith) to His presence. Jesus is the good news or gospel because He is ‘God with us.’ The Law, His Word, facilitates His dwelling amongst us. His sacrifice makes it possible for God to dwell within us forever, and the Law helps us learn to live accordingly. So the living oracles are part and parcel of the gospel – God with us.