Heaven and earth
'Heaven and earth' signify all the inner parts of the church, and 'sea and dry land' signify all its outer parts, as mentioned in Haggai 2:6. 'Heaven and earth' signify, in general, the internal and external church. In particular, they signify the internal and external, or the spiritual and the natural parts of a person.
In Psalm 89:13, they signify the higher and lower heavens, and also the internal and external church.
'Heaven and earth being finished, and all the host of them,' as mentioned in Genesis 2:1, signifies that mankind had been made spiritual.
'In heaven, on earth, and under the earth,' as mentioned in Revelation 5:3, signify the three heavens in orderly succession, from the highest to the lowest.
'Heaven and earth' in scripture signify the heaven and earth which angels and spirits inhabit. In a spiritual sense, they signify the church amongst men.
(References: Apocalypse Explained 751; Arcana Coelestia 82; Haggai 2)
One
A company might have executives setting policy and strategy, engineers designing products, managers handling personnel and others handling various functions. They all do different things -- but if they're doing them with a shared underlying purpose, the company -- and the individuals in it -- will likely be successful. The Lord wants all human society to function in a similar way. We have different skills and individual loves, but if we all share a mutual love -- a love of serving others -- then society will function as one, will be a reflection of heaven and will be a good receptacle for the Lord's love. This can also happen within each of us, as we unify our talents and ideas around a central love. And in an abstract sense, it illustrates how a wide collection of varying ideas can be unified around a shared good intention. That is the kind of love pictured when “one” is used in the Bible, either as a specific number or in the sense of several people or objects “being one.” In more casual references -- when used to identify a specific person or object -- the meaning is relatively literal, and is connected to that person or object.