"'"Every grain offering you bring to the Lord must be made without yeast, for you are not to burn any yeast or honey in a food offering presented to the Lord. You may bring them to the Lord as an offering of the firstfruits, but they are not to be offered on the altar as a pleasing aroma."'" NIV translation
This offering could not contain yeast or honey and that is because it is a picture of the earthly life of Jesus Christ. Yeast (leaven) is forbidden because it is associated with sin and Jesus had to be the perfect sacrifice. To be the perfect sacrifice, He had to be without defect (sin). Honey is associated with natural sweetness and was forbidden because it was used to cover over the natural taste of things. This was a picture of the fact that the truth was not to be "sugar-coated". That truth was the fact that man could not be made righteous through their own efforts but only through the sacrifice of Jesus Christ.
Today, there are those that want to sugar-coat this truth in order to get along. We cannot do this and still trust in the fact that Jesus paid for our sins. It is also a reminder to us that our walk with Christ on this earth will not be one of compromise with this world. That does not glorify God and is not a pleasing aroma to Him.
"'"Season all your grain offerings with salt. Do not leave the salt of the covenant of your God out of your grain offerings; add salt to all your offerings."'" NIV translation
Salt is a preservative and was a symbol of the lasting promises of God. This was to be added to all of the grain offerings and is a picture of the fact that Jesus is eternal.
"'"If you bring a grain offering of firstfruits to the Lord, offer crushed heads of new grain roasted in the fire. Put oil and incense on it; it is a grain offering. The priest shall burn the memorial portion of the crushed grain and the oil, together with all the incense, as a food offering presented to the Lord."'" NIV translation
Grain that was the first and best part of the harvest was to be treated in a special way. This was because of the fact that Jesus was to be the firstfruits of the resurrection and these are a picture of Him.