Alternatively, the idea of firstfruits could mean that they are consecrated to God, which is what a worshipper did when he offered his sample of the harvest to God. The idea of consecration would be strengthened by the statement that their speech and character is now faultless. Heaven is a place of wonders and two of them will be the pure speech and faultless characters of those who once were sinners.
We should thank God for giving to us this interlude during which we can look ahead into the eternal world and see some of its glories. It is an encouragement for us to do so when life gets tough. And it is an encouragement also to realise that we are a lot closer to it than were the believers who first received this vision of heaven.