The feast mentioned in the verses above is the Feast of Tabernacles. It was a seven day feast (eventually an eighth day was added) and on each day a priest drew water from the Pool of Siloam
at the southwest corner of the City of David and carried the water in a golden pitcher up the street
that led to the Temple Mount on Mount Moriah. This was done in a joyful procession that included trumpets  and singing. On the Temple Mount the water was poured into a bowl by the altar of burnt offering.

The Mishnah says,

“He that never has seen the joy of the Water-drawing has never in his life seen joy.”

The ceremony symbolized four things:

1. Thanksgiving for God’s provision of water in the past
2. Prayer for rain for the coming year
3. The water of salvation mentioned in Isaiah 12:3 which was used by Isaiah to refer to this
   same Feast of Tabernacles and the Water-drawing ceremony which symbolized God’s salvation or deliverance for Israel: “With joy you will draw water from the wells of salvation.” (Isaiah 12:3)
4. In the Talmud this ceremony is done each of the seven days of the Feast of Tabernacles to represent the pouring out of the Holy Spirit. The Holy Spirit is the water of the salvation.

This feast, this water drawing/pouring ceremony, Isaiah’s words and the Jewish understanding of
the water and the Holy Spirit is the context of Jesus’ actions and words on the last day of the
Feast of Tabernacles on the Temple Mount in Jerusalem in 30 AD. On the eighth and final day
of the Feast no water was poured out. Instead, a prayer was offered asking God to send water.
It is at this time the teacher Jesus is no longer seen in his seated position from where he would
have instructed his gathered group of students. Instead, Jesus is said to be standing and making
a proclamation in a loud voice to this joyful crowd celebrating on the Temple Mount. In response to the Jewish prayer for water that final day of the feast, Jesus addresses the entire community on the Temple Mount

“On the last and greatest day of the festival, Jesus stood and said in a loud voice:
‘Let anyone who is thirsty come to me and drink. Whoever believes in me,
as the scripture has said, rivers of living water will flow from within them.’ “

The “loud voice” used by Jesus is exactly that, a loud voice proclaiming emphatically and with emotion for all the worshippers to hear and respond. Jesus is saying this ritual is fulfilled in him.
The Pool of Siloam, the water, the pouring, the rejoicing is all pointing to Jesus.

John explains that the person who receives the living water, or the Holy Spirit, for salvation will
himself become a source of that living water for others. The believer will not only be saved, but
will also be empowered to carry that salvation and deliverance to others.

John chapter 4 spoke of a well of living water that springs up for salvation of the individual believer. Here, in John chapter 7 that same spring of living water becomes a river that flows to minister to others through that individual believer. Once we are saved, we all become ministers of this living
water that delivered us! The Spirit of God saves us, and then, the Spirit of God empowers us!

"“Depend upon it. God’s work, done in God’s way, will never lack God’s supplies.”
– Hudson Taylor

Ancient Jews would place their dead on burial benches in tombs. After a year had passed the body would have decomposed. At this time relatives would return to the tomb to place the deceased person's bones in a stone box called an ossuary. This ossuary was covered with a lid and left in the tomb beside the ossuaries of other family members. In this practice there were two actual burials: one, when the deceased was laid on the burial bench; two, when their bones where gathered together and placed alongside their forefathers after the flesh had decomposed. When a follower of Jesus asked, "Lord, first let me go and bury my father," he was probably referring to waiting a year for the body to decompose and was not referring to the fact that his father just died and needed to be placed in a tomb.
(Luke 9:60) (more here)