Genesis 4v8-16 records the first act of murder as Cain kills his brother Abel in a jealous rage, it also demonstrates the serious consequences of sin as Cain is left wandering outside of the presence of God.

Genesis 4:8–16

8 Cain spoke to Abel his brother.¹ And when they were in the field, Cain rose up against his brother Abel and killed him. 9 Then the LORD said to Cain, “Where is Abel your brother?” He said, “I do not know; am I my brother’s keeper?” 10 And the LORD said, “What have you done? The voice of your brother’s blood is crying to me from the ground. 11 And now you are cursed from the ground, which has opened its mouth to receive your brother’s blood from your hand. 12 When you work the ground, it shall no longer yield to you its strength. You shall be a fugitive and a wanderer on the earth.” 13 Cain said to the LORD, “My punishment is greater than I can bear.² 14 Behold, you have driven me today away from the ground, and from your face I shall be hidden. I shall be a fugitive and a wanderer on the earth, and whoever finds me will kill me.” 15 Then the LORD said to him, “Not so! If anyone kills Cain, vengeance shall be taken on him sevenfold.” And the LORD put a mark on Cain, lest any who found him should attack him. 16 Then Cain went away from the presence of the LORD and settled in the land of Nod,³ east of Eden.

Footnotes

[1] 4:8 Hebrew; Samaritan, Septuagint, Syriac, Vulgate add Let us go out to the field
[2] 4:13 Or My guilt is too great to bear
[3] 4:16 Nod means wandering

(ESV)