This is a line from the Bible, written in Hebrew, in which God is talking to his son directly. In the past God used to talk to the ancestors through the prophets appointed by God himself. According to the context, after Jesus had provided purification of his sins he sat besides the majesty in heaven. There God declared Jesus as his son and told all angels to worship him. He continues by saying that everyone and everything in this world will perish and only you will remain. They all will wear out like a garment does and you will role them up like a robe. In the end only you will remain forever.