Sometime back I was told that Jesus will bear the marks of the nails on his hands and feet forever (eternity). Is there a scripture reference to back this up?
There is no scripture that explicitly says Christ will bear His scars for all eternity. However, they are part of His resurrected body. After Thomas insisted that he would not believe unless he saw the imprint of the nails, and put his finger into the place of the nails, and put his hand into His side, John 20:27 records the Lord Jesus telling Thomas, “Reach here with your finger, and see My hands; and reach here your hand and put it into My side; and do not be unbelieving, but believing.”
I believe that the scars on Jesus’ body are the most beautiful things in all of heaven, and we will want to fall down and worship Him and touch (and even kiss!) His scars with awe; they are excruciating proof of His love for us.