Parakletos is the word Jesus used for the Holy Spirit — from para (alongside) and kaleo (to call): one called to your side to help. The King James Version renders it Comforter, but it is a rich word that also means Advocate, Helper, Counsellor — the friend who stands with you, pleads your case, and strengthens you. Jesus called the Spirit another Comforter, meaning another of the same kind as himself.
The same word appears once more in the New Testament, applied to Jesus: we have an advocate (parakletos) with the Father, Jesus Christ the righteous. So the believer has two paracletes — Christ pleading for us in heaven, and the Spirit helping us on earth. The Spirit teaches, reminds, guides into all truth, and abides for ever: the constant companion Jesus promised he would never leave us without.
Parakletos in Scripture
But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.