Exodus 30:10

Aaron shall make an atonement upon the horns of it once in a year Namely, upon the day of atonement, (see Leviticus 16:18,) when the high-priest was to take it in his way as he came out from the holy of holies. This was to intimate, that the sins of the priests who ministered at this altar, and of the people for whom they ministered, put a ceremonial impurity upon it, from which it must be cleansed by the blood of atonement. This altar typified the mediation of Christ: the brazen altar in the court was a type of Christ dying on earth; the golden altar in the sanctuary was a type of Christ interceding in heaven. This altar was before the mercy-seat, for Christ always appears in the presence of God for us; and his intercession is unto God of a sweet-smelling savour. And it typified the devotions of the saints, whose prayers are said to be set forth before God as incense, Psalms 141:2. As the smoke of the incense ascended, so must our desires, being kindled with the fire of holy love. When the priest was burning incense, the people were praying, (Luke 1:10,) to signify that prayer is the true incense. This incense was a perpetual incense, for we must pray always. The lamps were dressed or lighted at the same time that the incense was burned, to teach us that the reading of the Scriptures (which are our light and lamp) is a part of our daily work, and should ordinarily accompany our prayers and praises. The devotions of sanctified souls are well-pleasing to God, of a sweet-smelling savour; the prayers of saints are compared to sweet odours, Revelation 5:8; but it is the incense which Christ adds to them that makes them acceptable; and his blood that atones for the guilt which cleaves to our best services. Yet, if the heart and life be not holy, even incense is an abomination, Isaiah 1:13.