The lion uses different roaring sounds depending on what he wants to communicate, like the roar to assure his pride of his protection, or the roar when he is gets ready to fight to defend his own, or the roaring sound when he calls back his wayward sons and daughters. These are all biblical examples of when God roars as the lion.
Marelize uses this, to give prophetic word of His roaring sounds at this point in time, especially His roar of calling back His prodigal sons and daughters, before Jesus, the Lion of Judah, comes back, to call us home for the marriage supper of the Lamb.