The day spoken of here is the day when the LORD will remove the iniquity of the land mentioned in Zechariah 3:9. In that day, you shall call every man your neighbor, but who's neighbor is this referring to? Every man's neighbor, or the LORD's neighbor? Well, could the answer be both?

In John 15:1, Jesus likens Himself as being a vine. In that same chapter, Jesus points out that anyone who does not abide in the vine is not part of Him, and whosoever is not part of Him has no part in God's inheritance. When we become a part of the vine of Christ through faith in His redemption from sin, which He purchased with His blood that was shed on the cross for the forgiveness of our sins, then we become a part of the Lord Jesus Christ through the work of Christ He has done while He sojourned on this earth. If we rest on Christ's work, which He has done on the cross, then we will be able to partake in His righteousness, which are the basic fruits growing from the vine of Christ.

Nathanael was found under a fig tree in John 1:48, and he bore good fruit through His confession of Jesus being the Christ. Nathanael was probably thinking about the passage in Zechariah 3:8-10, which mentions the Hebrew version of Jesus' name, Joshua, and a prophecy, which reads, "I will bring forth my servant the BRANCH." This branch, the Messiah prophesied which would come to redeem Israel from evil, would remove the iniquity from the land in one day. Nathanael was perhaps thinking about the fig tree mentioned in Zechariah 3:10 and the coming of the King. A little later, when Jesus mentions He saw Him under the fig tree, right away Nathanael saw Jesus Christ as the fulfillment of the very prophesy mentioned in Zechariah 3:8-10, that He would be the King of Israel, which was the confession of Nathanael mentioned in John 1:49.