God didn't WANT animals to be killed, he WANTED people to live a life without sin but He, in His mercy, provided a system so that if they DID commit sin, then they could be reconciled to Him. Man, just as they do now in the age of grace, in his hard heartedness, abused this system and sinned with impunity because he could just take the life of an animal to pay for his misdeeds. This is WRONG! People sin now because they believe that Christ's blood will cover it but the Apostle Paul said we are NOT to live like that:
Romans 6 What shall we say, then? Shall we go on sinning so that grace may increase?
2 By no means! We are those who have died to sin; how can we live in it any longer?
11 In the same way, count yourselves dead to sin but alive to God in Christ Jesus.
12 Therefore do not let sin reign in your mortal body so that you obey its evil desires.
13 Do not offer any part of yourself to sin as an instrument of wickedness, but rather offer yourselves to God as those who have been brought from death to life; and offer every part of yourself to him as an instrument of righteousness.
14 For sin shall no longer be your master, because you are not under the law, but under grace.
They did the same thing in the Old Testament that people do today! Its WRONG, it is NOT the will of God at all and we should not be part of it. God did not WANT animals to die for people's sin, He wanted people to live right but they didn't and they murdered animals with impunity, which is not God's desire at all or consistent with who HE is.
Don't mistake the misdeeds of men with the nature or will of a Holy God. And we have to remember that God is not only a God of love and mercy, He is also a God of righteousness and justice and we wouldn't have it any other way, our own nature longs for justice and the punishment of wrongdoing....
I'm not sure really, how many people who claim to be Christian really are?
Jesus said: Matthew 7:
13 Enter ye in at the strait gate: for wide is the gate, and broad is the way, that leadeth to destruction, and many there be which go in thereat:
14 Because strait is the gate, and narrow is the way, which leadeth unto life, and few there be that find it.
15 Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
16 Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
17 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.
18 A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
19 Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.
20 Wherefore by their fruits ye shall know them.
21 Not every one that saith unto me, Lord, Lord, shall enter into the
kingdom of heaven; but he that doeth the will of my Father which is in