Samson did not know that the Lord had departed from him.  Then the Philistines took him and put out his eyes, and brought him down to Gaza.  (Judges 16:20c-21)

Biblically, Gaza is probably best associated with Samson, whom God turned over to his enemies as a result of his inveterate disobedience.

Gaza, עַזָּה or Ghazza, was one of the five city states of Philistia, the ancient kingdom of the Philistines.  And were a thorn in the side of Israel, as seen by God’s reprove of Joshua:

You are old, advanced in years, and there remains very much land yet to be possessed. This is the land that yet remains: all the territory of the Philistines and all that of the Geshurites,from Sihor, which is east of Egypt, as far as the border of Ekron northward (which is counted as Canaanite); the five lords of the Philistines—the Gazites, the Ashdodites, the Ashkelonites, the Gittites, and the Ekronites. (Joshua 13:1-3)

These five lords, the Hebrew is seren or tyrants (recalling that, like the Greek word, it was neutral, originally) ruled over Gaza, Ashdod, Ashkelon, Gath and Ekron.

This enmity was ‘anticipated’ by God:

Then it came to pass, when Pharaoh had let the people go, that God did not lead them by way of the land of the Philistines, although that was near; for God said, ‘lest perhaps the people change their minds when they see war, and return to Egypt.’ 

So, God led the people around by way of the wilderness of the Red Sea. And the children of Israel went up in orderly ranks out of the land of Egypt. (Exodus 13:17-18) 

But the trouble with the Philistines began much earlier, before forefather of Israel was conceived, that is Jacob the son of Isaac, was born:

Isaac departed from there and pitched his tent in the Valley of Gerar, and dwelt there. And Isaac dug again the wells of water which they had dug in the days of Abraham his father, for the Philistines had stopped them up after the death of Abraham.  (Genesis 26:18)

The Philistines were descendants of Ham, via his second son Mizraim; 

‘Mizraim begot… Casluhim, from whom came the Philistines…’ (Genesis 10:14) 

The Philistines were a sea-going people came from Crete, (in Hebrew, Caphtor) explaining why the Philistines did not venture far inland, instead populating the coastal plain between Gaza and Ashdod.  But God had already earmarked the Philistines for destruction:

The word of the Lord that came to Jeremiah the prophet against the Philistines…

Because of the day that comes to plunder all the Philistines,
To cut off from Tyre and Sidon every helper who remains;
For the Lord shall plunder the Philistines,
The remnant of the country of Caphtor. 
Baldness has come upon Gaza,
Ashkelon is cut off
With the remnant of their valley….

Seeing the Lord has given it a charge
Against Ashkelon and against the seashore?
There He has appointed it. (Jeremiah 47:1,4,5&7)

While the Philistines disappeared from the historical record, names of their cities and state endure to this day.  

Following the unsuccessful Jewish uprising, 132-5AD, the Roman province of Judea was subsumed into a larger entity, that of Syria Palestina.  ‘Palestina’ came from the Greek for Philistia.  Thus, the name for the region, Palestine, endured two millennia, and was used during the League of Nations mandate 1920-48, when administration of the region was granted to the British Empire.

Gaza, the great city of Philistia, was the theatre of conflict and so it remains, long after its people, the Philistines, vanished.  God declares through his prophet, the hostility He orchestrated is not fully outworked, yet there will be peace:

‘Did I not bring up Israel from the land of Egypt,
The Philistines from Caphtor…’ 

‘… I will not utterly destroy the house of Jacob’,
declares the Lord.
^‘For behold, I will command,
    and shake the house of Israel among all the nations
as one shakes with a sieve,
    but no pebble shall fall to the earth…’ 

Behold, the days are coming,’ declares the Lord,
  ‘when the ploughman shall overtake the reaper
    and the treader of grapes him who sows the seed;
the mountains shall drip sweet wine,
    and all the hills shall flow with it.’  (Amos 9:7,8b-9&13)