"To the City of Refuge!"

By Elizabeth Prata
Left, Illustrator of Charles Foster, The Story of the Bible, 1884, City of Refuge.
Asylum. Sanctuary Cities. Manslaughter. Innocent. These are judicial terms that are not new, the men of Bible times knew them and we know these terms today.
Our God is a God of justice. He knows what is in a man, and it's sin. He knows we hate and murder. He knows that when blood is shed, blood must pay. Therefore, God made it possible for wrongful shedding of human blood to be avenged. The nearest relative of the wrongfully killed person ("murderer") may hunt the perp down and kill him with no repercussions to himself. (Numbers 35:19, 21, Deuteronomy 19:12).
However, there are times when blood is shed accidentally, or unknowingly. This person is called a "Manslayer" as opposed to the aforementioned 'murderer'. If a man accidentally killed another man, God made a way for that person to be able to flee to a City of Refuge, so called in the Bible, and hurl himself upon the judicial investigation of the priests or elders of that city. Here's how Charles Spurgeon explains it:

You will remember that when the children of Israel were settled in Canaan, God ordained that they should set apart certain cities to be called the Cities of Refuge, that to these the man-slayer might flee for security. If he killed another unawares, and had no malice aforethought, he might flee at once to the City of Refuge; and if he could enter its gates before the avenger of blood should overtake him, he would be secure. 

Cities of Refuge were carefully selected at strategic locations so that no person living in the Land would have to run far to access it. They were equally spread out. A person anywhere in the Land could reach them in a day or less. The Cities of Refuge were open to strangers, too.
Cities of Refuge (source Smith's Bible Dictionary) were six Levitical cities specially chosen for refuge to the involuntary homicide until released from banishment by the death of the high priest. (Numbers 35:6,13,15; Joshua 20:2,7,9) There were three on each side of Jordan.

Source

Kedesh, in Naphtali. (1 Chronicles 6:76)
Shechem, in Mount Ephraim. (Joshua 21:21; 1 Chronicles 6:67; 2 Chronicles 10:1)
Hebron, in Judah. (Joshua 21:13; 2 Samuel 5:5; 1 Chronicles 6:55; 29:27; 2 Chronicles 11:10)
On the east side of Jordan -
Bezer in the Wilderness, in the tribe of Reuben, in the plains of Moab. (4:43; Joshua 20:8; 21:36).
Ramoth-Gilead, in the tribe of Gad. (4:43; Joshua 21:38; 1 Kings 22:3)
Goolan in Bashan, in the half-tribe of Manasseh. (4:43; Joshua 21:27; 1 Chronicles 6:71)
What you had to do, if, say you were chopping wood and your axe head flew off and killed the man next to you, is run to the city. Upon arrival, you would have to tell the elders what happened. You'd have to make it there before the 'avenger of blood', usually the nearest next of kin to the dead man, gets you and kills you.
The elders would provide you a place to stay and food, until they met to discuss your case.
If the case is adjudicated as accidental, you would be allowed to remain in the city of refuge freely until the High Priest died. After that you could go home. If you left the city of refuge prior to the death of the High Priest, the avenger of blood could perform the death penalty without penalty to himself.
I find all this amazing, that God provided opportunities for justice in these cases. What I find even more fascinating is just how seriously the Israelites took the cities of refuge.
These cities of refuge were a fact, real cities with real roads leading up to them. The roads leading up to it would need to be maintained. They erected signs at intervals so that the fleeing man-slayer would know where to go. They maintained the signs regularly also. Spurgeon again from the same link as above:

We are told by the rabbis that once in the year, or oftener, the magistrates of the district were accustomed to survey the high roads which led to these cities. They carefully gathered up all the stones, and took the greatest possible precautions that there should be no stumbling-blocks in the way which might cause the poor fugitive to fall, or might by any means impede him in his hasty course. We hear, moreover, and we believe the tradition to be grounded in fact, that all along the road there were hand-posts with the word "Refuge" written very legibly upon them, so that when the fugitive came to a crossroad, he might not need to question for a single moment which was the way of escape; but seeing the well-known word "Refuge," he kept on his breathless and headlong course until he had entered the suburb of the City of Refuge, and he was then at once completely safe. Spurgeon

It's true about the roads and the signs, not just tradition. This is from the Jewish Encyclopedia, written after Spurgeon preached that message:

Corresponding to the care for the proper location of these cities were the other ordinances referring to them. The roads leading to them were marked by sign-posts at the crossroads, with the inscription "Miḳlaṭ" (Refuge); the roads were very broad—32 ells, twice the regulation width—smooth and level, in order that the fugitive might not be hindered in any way (Sifre l.c.; Tosef. l.c. 5; Mak. 10b; B. B. 100b). The cities chosen must be neither too small nor too large: in the former case a scarcity of food might arise, and the refugee might consequently be forced to leave his Asylum and imperil himself; in the latter case the crowds of strangers would make it easy for the avenger of blood to enter undetected. There were other measures of precaution in favor of the refugee. Dealing in weapons or implements of the chase was forbidden in the cities of refuge. Furthermore they had to be situated in a populous district, so that a violent attack by the avenger of blood might be repelled, if necessary. Jewish Encyclopedia, 1906

God is incredible the way He set up society in those days. I look forward to the real, actual Millennial Kingdom, the 1000 year kingdom when God fulfills His promises to Israel and we live with Him on earth- Jesus as King and David ruling as under-King.
Meanwhile, the spiritual lesson is this: though there are sanctuary cities on earth today, there is one city to which every person on earth should flee. Or sins are high crimes against a Most Holy God. We all deserve the death penalty. However, if we flee to Jesus the High Priest, we may throw ourselves at His feet and plead His blood to cover our sins. If we repent and trust Him as Savior, He will forgive the crime and we will escape the penalty- which is death.
And since Jesus as High Priest never dies, we will live without fear of death forever.
Hallelujah!