These are some very important questions one must ask, Should I worship God my way? Should I follow what is popular today? Or should I follow and worship God's way.
Genesis 3:21 Unto Adam also and to his wife did the LORD God make coats of skins, and clothed them.
When Adam and Eve sinned by eating a forbidden fruit, they would surely die. According to God's Word, the penalty of Sin is death. Something had to die to cover their sin. God provides the very first sacrifice and made coats of skins. An animal had to die for their covering.
Genesis 4:3-7 And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD. And Abel, he also brought of the firstlings of his flock and of the fat thereof. And the LORD had respect unto Abel and to his offering: But unto Cain and to his offering he had not respect. And Cain was very wroth, and his countenance fell. And the LORD said unto Cain, Why art thou wroth? and why is thy countenance fallen? If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee [shall be] his desire, and thou shalt rule over him.
According to Arthur W. Pink, Gleanings in Genesis, "In bringing the offering he did, Cain denied that he was a sinful creature under the sentence of divine condemnation. He insisted on approaching God on the ground of personal worthiness. Instead of accepting God's way, he offered to God the fruits of the ground, which God had cursed. He presented the product of his own toil, the work of his own hands, and God refused to receive it." Cain did it his way!
Hebrews 11:4 By faith Abel offered unto God a more excellent sacrifice than Cain, by which he obtained witness that he was righteous, God testifying of his gifts: and by it he being dead yet speaketh.
Abel on the other hand, by his faith provided animals and made sacrifices according to God's way. God respected Abel's offerings.