"Bring no more futile sacrifices; incense is an abomination to Me.The New Moons, the Sabbaths, and the calling of assemblies—I cannot endure iniquity and the sacred meeting." Isaiah 1.13
Offerings, sacrifices and religious zeal cannot make up for a person's sins and they are not pleasing to the Lord. The children of Israel know this very well. It was not a difficult task for them to fulfil religious obligations. The hard part was to stay away from sin.
Wouldn't it be the same as a husband full of lovers saying to his wife, "I've given you comfort, good houses, expensive cars, jewellery, money, and everything else you need..."? But she says, "I don't have the most important thing: you."
"Fools and blind! For which is greater, the gold or the temple that sanctifies the gold? [...] Fools and blind! For which is greater, the gift or the altar that sanctifies the gift?" Matthew 23.17-19
Tithes and offerings carry a revelation in itself: what is in the offering giver's heart.
Firstfruits show faithfulness and offerings reveal love.
While there was no sin in the world, tithes and offerings were not necessary, since the communion between the creature and the Creator was perfect. With sin came the moral and spiritual corruption. Therefore, God established the tithe and offerings to prove the heart of those who approached Him.
“Has the LORD as great delight in burnt offerings and sacrifices, As in obeying the voice of the LORD? Behold, to obey is better than sacrifice, And to heed than the fat of rams." 1 Samuel 15.22
The offering of material goods without obedience to God's Word does not work. What good would it be if a prostitute, for example, offers one month worth of her gain but keeps selling her body? Would the Lord God accept such an offering?
The offering is something spontaneous from the soul that expresses sincere love. But the sacrifice involves total surrender of body, soul and spirit. It sacrifices body and soul. There is no reservation on the sacrifice. Saul sacrificed the body of an animal, but did not sacrifice his will in order to do God's will.
"I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, which is your reasonable service." Romans 12:1
Contradicting the inclinations of the heart and turning down what this world has to offer is a daily exercise that true disciples of the Lord Jesus Christ must do. This includes spiritual offerings, living sacrifices to the Lord God. In return, He fulfills the desires of our heart.