Revelation 4:1 Meaning

1After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.

2And immediately I was in the spirit: and, behold, a throne was set in heaven, and one sat on the throne.

3And he that sat was to look upon like a jasper and a sardine stone: and there was a rainbow round about the throne, in sight like unto an emerald.