2 Kings 14:5

Now when he became strong in the kingdom, straight away he put to death those servants who had taken the life of the king his father;

Genesis 9:6

Whoever takes a man's life, by man will his life be taken; because God made man in his image.

Exodus 21:12-14

He who gives a man a death-blow is himself to be put to death.

Numbers 35:33

So do not make the land where you are living unholy: for blood makes the land unholy: and there is no way of making the land free from the blood which has come on it, but only by the death of him who was the cause of it.

2 Kings 12:20-21

And his servants made a secret design and put Joash to death at the house of Millo on the way down to Silla.

2 Chronicles 25:3-4

Now when he became strong in the kingdom, he put to death those men who had taken the life of the king his father.

Treasury of Scripture Knowledge

Summary

And it came to pass, as soon as the kingdom was confirmed in his hand, that he slew his servants which had slain the king his father.

General references

Bible References

That he slew

Genesis 9:6
Whoever takes a man's life, by man will his life be taken; because God made man in his image.
Exodus 21:12
He who gives a man a death-blow is himself to be put to death.
Numbers 35:33
So do not make the land where you are living unholy: for blood makes the land unholy: and there is no way of making the land free from the blood which has come on it, but only by the death of him who was the cause of it.

His servants

2 Kings 12:20
And his servants made a secret design and put Joash to death at the house of Millo on the way down to Silla.
2 Chronicles 25:3
Now when he became strong in the kingdom, he put to death those men who had taken the life of the king his father.

General references

Deuteronomy 24:16
Fathers are not to be put to death for their children or children for their fathers: every man is to be put to death for the sin which he himself has done.

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain