When putting a coffin on the deceased, we usually say some courtesy words to express our respect and memory for the deceased. Here are some possible polite expressions:
1. "Please rest in peace, your soul has ascended to heaven."
2. "May you always be safe in heaven."
3. "Please rest assured that we will miss you forever and always remember your position in our hearts."
4. "May God bless your soul and let you rest in peace."
These words can be adjusted and expressed according to specific funeral ceremonies and family customs, but in general, they express respect and mourning for the deceased.