The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
incense
Altar of incense, type of Christ our intercessor (Joh 17:1-26); (Heb 7:25) through whom our own prayers and praises ascend to God; (Heb 13:15); (Rev 8:3); (Rev 8:4) and of the believer-priest's sacrifice of praise and worship (Heb 13:15).
shittim
That is, acacia.
strange
Compare (Lev 10:1-3); two prohibitions are given concerning worship:
(1) No "strange" incense is to be offered. This speaks of simulated or purely formal worship.
(2) No "strange" fire was permitted. This refers to the excitation of "religious" feelings by merely sensuous means, and to the substitution for devotion to Christ of any other devotion, as to religious causes, or sects.
Compare (Co1 1:11-13); (Col 2:8); (Col 2:16-19).
(See Scofield) - (Exo 30:38).
atonement
(See Scofield) - (Exo 29:33).
This they shall give
Compare (Exo 38:25-27).
Silver thus becomes a type of redemption.
(See Scofield) - (Exo 26:19).
laver
Laver, type of Christ cleansing us from defilement, and from "every spot or wrinkle or any such thing" (Joh 13:2-10); (Eph 5:25-27). It is significant that the priests could not enter the holy place after serving at the brazen altar till hands and feet were cleansed.
oil
Anointing oil, type of the Holy Spirit for service (Act 1:8).
frankincense
Frankincense is not to be confounded with incense (to which it was to be added), as it is often used apart from incense. We are told what composed the incense -- never in Scripture what the frankincense was. All speaks of Christ -- the sweet spices of those perfections which we may apprehend, the frankincense of that which God saw in Jesus ineffable.
smell
What is condemned here is making worship a mere pleasure to the natural man, whether sensuous, as in beautiful music to please the ear, or eloquence, merely to give delight to the natural mind.