That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me.
This prayer should be one of the most comforting words Jesus ever spoke to His followers. It’s just so lovely, a prayer of unity, of agreement and hope only a Christian could understand.
Jesus is praying for unity with you, and God. A unity that only comes with the filling of the Holy Spirit.
The Holy Spirit is the connection between God, Jesus and yourself. Using a light switch as a metaphor is a very simple way to gain some understanding. When you accept Jesus as your Lord and Savior you can receive the gift of the Holy Spirit if you so desire.
If a son shall ask bread of any of you that is a father, will he give him a stone? or if he ask a fish, will he for a fish give him a serpent?
Jesus is talking about the Holy Spirit, if you’re saved and ask for the infilling of the Holy Spirit, He will not give you a demon.
Just as with a light switch, when you pray, you flip on the switch, the power flows through the line to the bulbs and you have a three-way connection, of course in this feeble representation God & Jesus are always powered up, really the power flows in the opposite direction towards you. The amazing attribute is that the same Holy Spirit is in all believers, and with the Holy Spirit we can all be in unity through prayer.
This is how the church unites, and how God comforts.