This is inaccurate. People who are neither employed nor unemployed are not considered part of the labor force. For instance this would include retired persons, students, people taking care of children or other family members, and those who have no desire at all to work. Here [1] is a brief on the reasons people are not counted.

[1] - https://www.bls.gov/opub/btn/volume-4/people-who-are-not-in-...

Source? People tend to put much more thoughtful words in his mouth after the fact trying to make what he says seem more reasonable, but if you have a source I'd gladly review it.

In the meantime, politifact has a good breakdown of what he says about the issue and where the numbers come from (spoiler, they make some wild assumptions) [1].

[1] http://www.politifact.com/truth-o-meter/statements/2015/sep/...