Dear Member (Neutral Singh),
When in Gurbani the word Guru comes it means 'Karta Purakh'.
Gurparsadi means that you get is a parshad from Guru i.e. Karta Purakh'.
The concept of Gurparsadi can be understood by the following example.
Take an iron pin and a magnet. Keep them a sufficient distance say 5 cntimeters. Then with one finger you push the pin slowly towards tha magnet. Gradually the distance will deminish. At one perticular position the pin will lose contact with your finger, move towards the magnet and makes contact with out any further push from you finger. We all know, the magnet has pulled the iron pin. Some thing similar happens in 'Gurparsadi'.
In the same way, 'Karta Purakh' just pulls in the individuals who have qualified for his grace. This is natural, because we mortals donot know the ways on 'Karta Purakh', we with form and limited cannot comprehend 'The Ultimate'. The last lap of ones journey towards 'The Sat' has to be by the grace of 'Karta Purakh'. Till this happens we cannot experience 'The Sat'. When this happens it is termed as Gurparsadi - Guru i.e. 'Karta Purakh', 'The Sat' has blessed by revealing itself to you, this is the real parsad from 'The Guru'; nothing can be more than this.
You do not need any mediator. There is no one standing between the seeker and 'The Karta Purakh' except her/his ignorance. Guru Sahibs have enshrined their wisdon and teachings in Siri Guru Granth Sahib for you to do it yourself. They have abolished Guruship and priesthood.
What is realised in this age of knowledge that every one has to be a self learner, our Guru Sahib had given effect to it 300 years ago. Each Sikh has to be a self learner, there is no Guru in flesh an bone for her/him. Khalsa Jee you are a self learner, you do not need any mediator.
With love and respect for all.