The people having, besides their submission to the ceremony of the sprinkling of blood, declared their well-pleasedness in their God and his law, again and again, God here gives to their representatives some special tokens of his favour to them (for God meets him that rejoices and works righteousness), and admits them nearer to him than they could have expected. Thus, in the New Testament church, we find the four living creatures, and the four and twenty elders, honoured with places round the throne, being redeemed unto God by the blood of the Lamb which is in the midst of the throne, Rev 4:4, Rev 4:6; Rev 5:8, Rev 5:9. Observe, 1. They saw the God of Israel (Exo 24:10), that is, they had some glimpse of his glory, in light and fire, though they saw no manner of similitude, and his being no man hath seen nor can see, Ti1 6:16. They saw the place where the God of Israel stood (so the Septuagint), something that came near a similitude, but was not; whatever they saw, it was certainly something of which no image nor picture could be made, and yet enough to satisfy them that God was with them of a truth. Nothing is described but that which was under his feet; for our conceptions of God are all below him, and fall infinitely short of being adequate. They saw not so much as God's feet; but at the bottom of the brightness, and as the footstool or pedestal of it, they saw a most rich and splendid pavement, such as they never saw before nor after, as it had been of sapphires, azure or sky-coloured. The heavens themselves are the pavement of God's palace, and his throne is above the firmament. See how much better wisdom is than the precious onyx or the sapphires, for wisdom was from eternity God's delight (Pro 8:30), and lay in his bosom, but the sapphires are the pavement under his feet; there let us put all the wealth of this world, and not in our hearts. 2. Upon the nobles (or elders) of Israel, he laid not his hand, Exo 24:11. Though they were men, the dazzling splendour of his glory did not overwhelm them; but it was so moderated (Job 26:9), and they were so strengthened (Dan 10:19), that they were able to bear it. Nay, though they were sinful men, and obnoxious to God's justice, yet he did not lay his punishing avenging hand upon them, as they feared he would. When we consider what a consuming fire God is, and what stubble we are before him, we shall have reason to say, in all our approaches to him, It is of the Lord's mercies that we are not consumed. 3. They saw God, and did eat and drink. They had not only their lives preserved, but their vigour, courage, and comfort; it cast no damp upon their joy, but rather increased and elevated it. They feasted upon the sacrifice, before God, in token of their cheerful consent to the covenant now made, their grateful acceptance of the benefits of it, and their communion with God, in pursuance of that covenant. Thus believers eat and drink with Christ at his table, Luk 22:30. Blessed are those that shall eat bread in the kingdom of our Father, and drink of the wine new there.

The book of the covenant - The writing containing the laws mentioned in the three preceding chapters. As this writing contained the agreement made between God and them, it was called the book of the covenant; but as no covenant was considered to be ratified and binding till a sacrifice had been offered on the occasion, hence the necessity of the sacrifices mentioned here.
Half of the blood being sprinkled on the Altar, and half of it sprinkled on the People, showed that both God and They were mutually bound by this covenant. God was bound to the People to support, defend, and save them; the People were bound to God to fear, love, and serve him. On the ancient method of making covenants, see Clarke on Gen 6:18 (note); and see Clarke on Gen 15:18 (note). Thus the blood of the new covenant was necessary to propitiate the throne of justice on the one hand, and to reconcile men to God on the other. On the nature and various kinds of the Jewish offerings, see Clarke's note on Lev 7:1, etc.

Then went up Moses and Aaron, Nadab and Abihu,.... After the above things were done, the words of the Lord were told the people, and the book of the covenant read unto them, to which they agreed, sacrifices were offered, and the blood of them sprinkled on the altar, and on the people. The Samaritan version adds to these, Eleazar and Ithamar, the two younger sons of Aaron:

and seventy of the elders of Israel, who were called up to the mountain to the Lord, Exo 24:1.

Then went up Moses, and Aaron--in obedience to a command given (Exo 24:1-2; also Exo 19:24), previous to the religious engagement of the people, now described.

Nadab, and Abihu--the two oldest sons of Aaron [Exo 6:23].

seventy of the elders--a select number; what was the principle of selection is not said; but they were the chief representatives, the most conspicuous for official rank and station, as well as for their probity and weight of character in their respective tribes.