Leviticus 9:23

And Moses and Aaron went into the tabernacle of the
congregation
They went out of the court where the altar of burnt offering stood, and where Aaron had been offering the sacrifices; and they went into the holy place, where stood the altar of incense, the shewbread table, and the candlestick; and it is probable Moses went in with Aaron thither, to show him how to offer the incense, to order the shewbread on the table, and to light and trim the lamps of the candlestick; and so Jarchi observes, that he went in to teach him concerning the business of the incense; but it may be, it was also to pray for the people, as the Targum, and for the Lord's appearance to them, as was promised and expected, and that fire might descend on the sacrifices as a token of acceptance of them, as Aben Ezra notes:

and came out, and blessed the people;
Aaron had blessed them before, but now both Moses and Aaron blessed them, atonement being made by the sacrifice of Christ, and law and justice thereby fully satisfied; Christ and the law agree together in the blessing of the Lord's people; way was hereby made for the communication of blessings to them, consistent with the law of God, and his holiness and justice, ( Galatians 3:10 Galatians 3:13 Galatians 3:14 ) :

and the glory of the Lord appeared unto all the people:
some visible signs of his glory, some very great splendour or lustre, or breaking forth of his glory; or Christ, the glory of the Father, appeared in an human form, as a pledge of his future incarnation, when all the above sacrifices, which were types of him, would have their accomplishment; and this being immediately upon the offering of them, may signify that the glory of God greatly appears in the sacrifice and satisfaction of Christ, and in the redemption and salvation of his people in that way, ( Psalms 21:4 ) ( 85:10 ) and the glorious and gracious presence of God is enjoyed by his people, in consequence of the propitiatory sacrifice of Christ, which was signified by the mercy seat, from whence the Lord communed; and it is through Christ, his blood and sacrifice, saints have access to God, and fellowship with him, ( Ephesians 2:18 ) ( 3:12 ) ( 1 John 1:3 ) .