The Gospel commentary can be found here. The NT reading is
Chrysostom tells us that wonderful indeed were the things in the Temple, the Holy of Holies. while those things which occurred at Mt Sinai were terrible – ‘a blazing fire, and darkess, and gloom, and a tempest (Deut 33:2). But the New Covenant was given in quite another way – through Jesus Christ, where there is nothing frightening, and where God reveals himself to us more fully than ever before, and through whom alone can we be saved. Where in the OT men feared that to hear the word of God was to die, (Ex 20:19) we know that the Word of God is life, and through Him we shall inherit life eternal.
Instead of Moses, we get Jesus, and instead of the people ‘innumerable angels’. When he speaks of the ‘first born’ he means the faithful – those who are saved in Christ. From the first, therefore, the Israelites were themselves the cause of God’s being manifested in the flesh, and we know, as they did not, that there is no need to fear God speaking to us – provided we follow His precepts through the revelation of Christ. We hear the voice not through the storm or the dark or the fire, but through Jesus Christ.
St Ambrose reminds us that we must always be anxious to hear the Word of God and to obey it. We must be on the watch always – the soul knows no peace until it finds it in Christ. Just as Christ raised Adam and Eve, so too did he raise Abel, for his offerings were pleasing to God. Jesus offered himself as the one perfect sacrifice acceptable to God. We are purified by that precious blood. What was prefigured in the Old testament is revealed more full in the New, and we are to attend on Christ and the revelation and the Good News he brings. There, alone, can salvation be found.