Your work with the Tesseract is what drew Loki to it, and his allies.
6 seconds sound clip from the The Avengers (2012) movie soundboard.
You can hear this line at 01:08:39 in the Blu-ray version of the movie.
Quote context
[...]
- We learned that not only are we not alone, but we are hopelessly, hilariously, outgunned.
- My people want nothing but peace with your planet.
- But you're not the only people out there, are you? And you're not the only threat.
- The world's filling up with people who can't be matched, that can't be controlled.
- Like you controlled the Cube?
- Your work with the Tesseract is what drew Loki to it, and his allies.
- It is a signal to all the realms that the Earth is ready for a higher form of war.
- You forced our hand. We had to come up with something.
- A nuclear deterrent. Because that always calms everything right down.
- Remind me again how you made your fortune, Stark.
[...]