Symbolic of one of the witnesses mentioned in the Bible, an olive tree in a gentile land, the other olive tree is Israel, when the two finally fully worship god dressed in sackcloth through Jesus, Jesus shall then return on a cloud in the last days. The two witnesses are kingdoms. Sackcloth means you have to repent your sins as those who have humbled themselves before God have done over the centuries dressed in sackcloth. In other words you are in the last days, so humble yourselves and repent of your sins as the lord is about to return! You will not know the hour or the day when your Lord God returns, look up as your redemption draws nigh.