Leviticus 5:11

But if he be not able to bring two turtledoves, or two young pigeons,.... Which is supposing a man to be in the poorest circumstances he can well be; and such is the grace and goodness of God, that he has provided for the atonement and forgiveness of the poorest, as well as of the rich:

then he that hath sinned shall bring for his offering the tenth part of an ephah of fine flour for a sin offering; which is an omer, Exodus 16:36 and is as much as a man can eat in one day, as Aben Ezra remarks:

he shall put no oil upon it, neither shall he put [any] frankincense thereon; to distinguish it from the common meat offering, which had both, Leviticus 3:1 and to make it as easy, and as little chargeable to the poor as possible, both oil and frankincense being things of value; and some think that these were prohibited, to show that atonement and forgiveness, and even the salvation of men, are not owing to grace in them, comparable to oil, or to their prayers, signified by frankincense, and so to any or all of their duties, but to Christ alone, and his atoning sacrifice: or these were forbidden, because emblems of joy and gladness, and therefore not so proper at a confession of sin, and humiliation for it: or rather to show how disagreeable and offensive sin was to the Lord, being contrary to grace, of which oil was an emblem, and far from being acceptable to him, which frankincense might signify; and therefore being prohibited, might denote how unacceptable, yea nauseous, sin is to him; which agrees with the reason given;

for it [is] a sin [offering], and therefore must not be honoured, as Jarchi, or must have everything removed from it that is beautiful and amiable, as Ben Gersom, such as oil and frankincense.