Why did Israel impose a blockade on the Gaza Strip after Hamas took control?

In autumn 2007, following Hamas’s takeover of the Gaza Strip from the Palestinian Authority, Israel declared the territory a "hostile entity" and imposed a blockade.123

The primary reasons for this policy included:

• Security Concerns: The blockade was implemented in response to the rise of Hamas, a militant group that has historically maintained that waging holy war against Israel is a religious duty.23
• Rocket Attacks: Israel sought to counter sustained rocket assaults launched from the Gaza Strip into Israeli territory.13
• Sanctions: As part of the blockade, Israel approved a series of sanctions that included border closures, heavily restricted imports, and power cuts to pressure the Hamas-led government.13

In January 2008, Israel further tightened these measures by completely sealing its border with the Gaza Strip and temporarily halting fuel imports in an effort to stop the ongoing rocket fire. Over the following years, the blockade has been subject to various adjustments, including periodic easing of restrictions to incentivize cease-fire agreements.14