19 The foundations of the city wall were adorned with every kind of jewel: the first foundation is jasper, the second sapphire, the third chalcedony, the fourth emerald
The material used for the new city was made of precious stones that would surpass the wealth of the earth.
In Exodus 28:16-20, the breastpiece for making decisions was placed on the ephod which was for the priest to put on for seeking direction from the Lord. The names of the 12 tribes of Israel were engraved on these stones [Exodus 28:11].
The reason God wanted the names of Jacob sons to be engraved on the gemstones was to show how precious they are to Him.
In the same way, the Lord will construct the new city with precious stones which will be for the coming and going of the saints who are to Him highly valued in His sight.
20 the fifth sardonyx, the sixth carnelian, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, the twelfth amethyst.
All of the gemstones are in different colors which will display their beautiful colors when God’s light pierces through them.
21 The twelve gates are twelve pearls; each individual gate was made of a single pearl. The main street of the city was pure gold, transparent as glass.
The phrase “The twelve gates are twelve pearls” The word pearl in Scripture means something that is holy to God [Matthew 7:6]. In Matthew 13:44, a pearl is considered priceless [highly valuable or unattainable without help] and it refers to the kingdom of heaven [to be with God]. In Matthew 13:11, the kingdom of heaven’s secret is only known through the Word of God which is understood through the Holy Spirit residing in a person’s heart.
The gate being pearls show that the Holy of Holies [the Father and the Son] will dwell within the city making it the kingdom of heaven.
Wherever God is there you shall have heaven.
22 I did not see a temple in it, because the Lord God the Almighty and the Lamb are its temple.
God the Father and God the Son, shall not dwell inside of a temple, but shall be above the city giving the new world its light, reflecting His glory.
The reason why there will not be a temple in the new earth is that in the Old Testament, God would only stay at a place that was made holy [the temple] by purifying it with blood [only through sacrifice can sin be atoned for making the person holy]. In the new earth, it will be completely holy, a sinless place because Jesus is our sacrifice who made us holy by placing our faith in Him.
23 The city does not need the sun or the moon to shine on it, because the glory of God illuminates it, and its lamp is the Lamb.
Space [the universe] as we know it shall not be [exist]. For the stars and the sun was to give humanity light, but it will no longer be necessary because the Lord will be our light.
Nighttime and darkness will no longer exist. No need to sleep to gain rest, for our strength and rest is in Christ who will give us a spiritual body like His that need no rest [sleep].