I would argue that the connection between the Greek polis and the hoplite style of warfare has to do with the structure and organization of Greek society. Many Greek poleis involved similar characteristics, such as evidence of town planning. There is evidence of Greek poleis having specific designated areas for public buildings, private buildings, and religious buildings. Most poleis also involved a city wall for protection.

As for the hoplite formation, there is also evidence of Greek planning. The formation was not a loose gathering of men but rather a tight formation that moved as a single unit. Each soldier carried a shield to his left, which, when held close together, formed a wall of shields protecting the soldiers behind them. It is clear that much like the structure of the Greek polis, there was also structure to the Greek hoplite strategy.

One final possible connection between the Greek polis and the hoplite formation could come from Greek ideas on equality. Within most poleis, all male citizens were considered to have equal political rights. I would argue that this equality can be seen in the hoplite formation as well. The formation was one of equality in which all men received the same protections. In fact, it was the general who took the most exposed position at the far right position of the front line, the only position without a shield for coverage.

Hoplites were citizen-soldiers who were expected to fight for their individual polis. All male citizens were considered potential soldiers and were expected to fight when called upon. They were also expected to furnish their own weapons and armor.

The relationship with the polis is somewhat limited, other than the fact that each hoplite was a citizen of the polis; mercenaries were used on occasion, but they were not considered hoplites. Originally, hoplite forces came to be because of warfare between the individual city states; however with time and the threat from Persia, the emphasis shifted from fighting other poleis to fighting enemies of the Greeks at large.

How was the development of the Greek polis and the hoplite style of warfare  related?

The rise of the hoplite style of warfare helped to democratize the system of power in the polis.

Before the hoplites, fighting was done by aristocrats on horseback.  These aristocrats also dominated the political life of the polis.  With the coming of the hoplite phalanxes, that changed.  Now, more men were fighting for the polis and that meant that more men wanted and had earned the right to participate in its affairs.  This led to a system in which men could participate in political life without being members of the elite.

So, by democratizing war, the hoplite style of warfare helped to democratize the polis.