In a general sense, mourning in the Bible represents a state of grief over the lack of desires for good and true ideas about life. This often happens when a church or an aspect of a church has fallen away from the Lord and has been devastated. It can also be when a new church or state of a church is soon to begin, and there is nothing yet in place. In particular, especially when paired with "weeping," "mourning" has do with the loss of all desire for good and the presence of evil; "weeping" in those cases has to do with the devastation of thought and knowledge.

'The spirit of God,' as in Genesis 1:2, signifies the divine mercy of the Lord.

'The spirit of God' denotes good from an interior level, so from the divine. The spirit of God is what proceeds from the divine, so from good itself, because the divine is good itself, and what proceeds from it is truth within which is good. This is what 'the spirit of God' signifies in the Word, because the spirit itself does not proceed, but the truth itself within which is good, the spirit being the instrument which produces it.

(References: Arcana Coelestia 19; Divine Love and Wisdom 100)