Abel was the second son born to Adam and Eve.  His brother Cain was a farmer and Abel was a shepherd.  They both made an offering to the Lord from the first fruits of their labor.  God looked with favor on Abel’s offering and rejected Cain’s. 

Abel is listed in Hebrews, Chapter 11, in the Hall of Faith and was declared to be a ‘righteous man.”. Let’s review the Biblical account of Abel's sacrifice that is found in Genesis 4:2-8

“Now Abel kept flocks, and Cain worked the soil.  In the course of time Cain brought some of the fruits of the soil as an offering to the LORD. And Abel also brought an offering—fat portions from some of the firstborn of his flock. The LORD looked with favor on Abel and his offering, but on Cain and his offering he did not look with favor. So Cain was very angry, and his face was downcast.  Then the LORD said to Cain, “Why are you angry? Why is your face downcast? If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it.” Now Cain said to his brother Abel, “Let’s go out to the field.”While they were in the field, Cain attacked his brother Abel and killed him.”

If we review verses 6 and 7 we can see where both Cain was given the opportunity  to present  a more acceptable offering to the Lord after his offering was rejected (not looked upon with favor) by God:

“Why are you angry? Why is your face downcast? If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it.” Genesis 4:6, 7

It seems that Cain knew what he had to do to present an acceptable offering to God but refused to do so.  Cain seemed to have had a wrong attitude and would not worship God as he knew how. Cain became angry and killed his brother.  Abel is listed as the first martyr in the Bible.  Cain is listed as the first murderer.

From this lesson, we can fully understand the importance of obedience is to God.  Abel was obedient and presented the best of his flock unto God (Genesis 4:4). God Confirmed Abel’s righteousness when He accepted Abel’s offering.  God also affirmed his obedience as righteousness in Hebrews 11:4:

“By faith Abel brought God a better offering than Cain did. By faith he was commended as righteous, when God spoke well of his offerings. And by faith Abel still speaks, even though he is dead.”

 We can also see that God’s commands are to be followed and obeyed.  By faith Abel brought God a better offering than Cain did. By faith he was commended as righteous, when God spoke well of his offerings. And by faith Abel still speaks, even though he is dead. 

We must be willing and obedient to the call and mandates of God.

“If you keep My commandments [if you continue to obey My instructions], you will abide in My love and live on in it, just as I have obeyed My Father's commandments and live on in His love.” John 15: 10