It is narrated from Sa'id bin al-Musayyib (may Allah have mercy on him) that the Messenger of Allah (ﷺ) said: "The mortgaged item will not be withheld from the one who has mortgaged it; the mortgager has the benefit of the mortgaged item and he will also bear its liability." Imam Shafi'i (may Allah have mercy on him) said: "'Ghunmah' means its increase and benefit, and 'ghurmah' means its destruction or loss."
Hadith Referenceمسند الإمام الشافعي / كتاب الرهن والقراض والحجر والتفليس واللقطة / 1477
Hadith Takhrijاسناده ضعیف لارساله ولعنعنة ابن شهاب، اخرجه الدار قطنی 31/3 ، 33 - والحاكم : (51/2)۔