1. GOD, NOT MAN, DETERMINES WHAT CONSTITUTES ACCEPTABLE WORSHIP.
"Speak to the children of Israel, and say to them: 'When any one of you brings an offering to the LORD, you shall bring your offering of the livestock--of the herd and of the flock. If his offering is a burnt sacrifice of the herd, let him offer a male without blemish; he shall offer it of his own free will at the door of the tabernacle of meeting before the LORD. Then he shall put his hand on the head of the burnt offering, and it will be accepted on his behalf to make atonement for him. He shall kill the bull before the LORD; and the priests, Aaron's sons, shall bring the blood and sprinkle the blood all around on the altar that is by the door of the tabernacle of meeting. And he shall skin the burnt offering and cut it into its pieces. The sons of Aaron the priest shall put fire on the altar, and lay the wood in order on the fire. Then the priests, Aaron's sons, shall lay the parts, the head, and the fat in order on the wood that is on the fire upon the altar; but he shall wash its entrails and its legs with water. And the priest shall burn all on the altar as a burnt sacrifice, an offering made by fire, a sweet aroma to the LORD.'"Look at the detail God provided for their offerings--and we only read the instructions for a burnt sacrifice of the herd! There were other very detailed instructions given for other types of sacrifices (as the book of Leviticus shows). Friends, don't ever think that God doesn't care how we worship Him! This amount of detail clearly demonstrates that God determines what is acceptable worship, not us (cf. John 4:24; Col. 2:23).
2. GOD EXPECTS THE BEST OF WHAT MAN OFFERS HIM.
Leviticus 3:16 - "And the priest shall burn them on the altar as food, an offering made by fire for a sweet aroma; all the fat is the LORD's."
The fat was considered to be the best part, and all the fat belonged to God! God has always wanted the best of what man offers Him (cf. Deut. 26; Matt. 6:33).
3. GOD DOES NOT EXPECT THE POOR TO GIVE THE SAME AS THE RICH.
Leviticus 5:7,11 - "If he is not able to bring a lamb, then he shall bring to the LORD, for his trespass which he has committed, two turtledoves or two young pigeons: one as a sin offering and the other as a burnt offering...But if he is not able to bring two turtledoves or two young pigeons, then he who sinned shall bring for his offering one-tenth of an ephah of fine flour as a sin offering..."
God is certainly fair. He did not require as much financially of the poor as of the rich. If you couldn't bring a lamb, you could bring two birds. If you couldn't bring two birds, you could bring flour. God expects all to give liberally today (cf. II Cor. 9:6,7), though the specific amount will differ based upon how wealthy we are financially.