Isaiah 43: 24-26. Thou hast bought Me no sweet cane with money, neither hast thou filled Me with the fat of thy sacrifices: but thou hast made Me to serve with thy sins, thou hast wearied Me with thine iniquities. I, even I, am He that blotteth out thy transgressions for Mine own sake, and will not remember thy sins. Put Me in remembrance; let us plead together; declare thou, that thou mayest be justified.”
Sweet cane, called sweet calamus, was used in the incense that Israel made for worship. Some was grown in Arabia, and India, and an inferior quality in Egypt and Syria. The kind used by Israel was brought from afar (Jer. 6:20)
Filling God with the fat of sacrifices simply meant to satisfy Him by meeting His requirements according to the law of Moses .
A paraphrase of verse 25 could be, “Instead of serving Me in holiness and righteousness, and worshiping Me with sacrifices and offerings to atone for sin, you have served in your sins and burdened Me with your iniquities.”
In spite if the sin of His people, God promises that He will indeed forgive them (this promise presupposes a period of their coming to repentance, which will not happen in a national sense until the Millennial reign. The idea of blotting out sins is taken from the custom of keeping accounts and canceling or blotting out the charge when the debt is paid. Thus God promised to cancel the sins of Israel and blot them all out. When this is done no punishment can be exacted for sins, and the people forgiven must be treated is pardoned friends.
Truly, what a kind and loving God we serve.