Chi Square Null Hypothesis Rejection

I am watching a youtube video on hypothesis testing. At around the 6 minute mark, the lecturer says for the chi square example that because the test value is HIGHER than the critical statistic for chi square, that the null cannot be rejected.

Can someone please explain why you would reject the null when the test value is higher than the critical stat?

Look at Ha: σ2 < 36.

This is a left-tail test.