The saying ```“RIP”``` meaning Rest In Peace have become popular with many Muslims today in prayers for their dead ones. This saying is a way and path of the 'Ahlul Kitab' and it’s not from the beautiful prayers our beloved Prophet( Peace and blessings of Allah be upon him) has taught us.
And it’s not a prayer but just a mere saying which doesn’t imply anything requesting Allah Of His mercy and forgiveness for the dead. Islam is a complete and perfect religion so follow that which was brought to you by Islam through the teaching Prophet Muhammad (SAW) and do not follow the way of the People of the Book' and their like. As Muslims, We can easily say in prayers for our dead ones:
*1.* _May Allah forgive him or her_
*2.* _May Allah have mercy on him or her_
*3.* _May Allah grant him or her Paradise_
*4.* _May Allah overlook his or her faults ....._ and the like.
Otherwise just saying ```RIP``` cannot benefit the dead anything.