וַיֹּ֨סֶף ע֥וֹד דָּוִ֛ד אֶת־כָּל־בָּח֥וּר בְּיִשְׂרָאֵ֖ל שְׁלֹשִׁ֥ים אָֽלֶף׃
And David again gathered together all the chosen men of Israel, thirty thousand.
Read kabbalistic (mystical) interpretation of II Samuel 6:1: and classical mystical sources.