Does every action has a reaction immediately or later in this world?
For that I don't agree.. But every action of a person is counted for the life he is inevitably to live hereafter...
Immediately or later, i would say both.
It depends on how strong is the karma,
That's why Karma is related with Kala (Sanskrit for time)
Every experience / action (Karma) always has the dimension of Impact / Implication (What is the event), Where (Space) and When (Time)
As per quran every action is recorded and every action of a person has value positively or negatively... He is responsible for the life after death through his actions (karma) in the given life... God won't discard a single action of a person in vain..
Every Karma is recorded in the universal cloud storage.
The "Universal Database of Experience / Action / Karma".
In Hinduism this cloud storage is being labeled as "Akashic Record".
The sanskrit word "Akash" by itself it means "Foundation for Space and Time", and only recently today's scientist labeled the same thing as "Gravitational Field". And yes when space and time are being destroyed, such as what can be observed in what happened in a Black Hole, then only the Data / Information will remain. As it's recorded in the "Akash" the foundational layer of Space and Time fabric.
But if one expects every action bounce back in this world itself then I don't think it is sensible to claim so.. If that is true then there is no point of looking for forgiveness.. And no point of living this current life with full of hardships and tests... We are created to be tested.. So every action is meaningful.. It is a lesson to choose the right path.. And it is not a life to be punished for every action in this world itself. . Unless God will..
If God is to punish for every action of human being He won't spare anyone on the earth. Coz we are vulnerable against Creator's preference. But God chooses to pardon us and give life span to correct our actions..
But every karma (action) definitely will be repaid in its entirety...
There's actually only one absolute reality, Hinduism call this Brahman, the boundless, the eternal, the everything, never created and never end. The awareness aspect of Brahman is then labeled as "Atman", The ultimate persona, the ultimate identity. The ultimate "I AM". The equivalent english word for Atman is perhaps "Consciousness" and in Arabic the closest word might be "Nafs".
The Atman / ultimate consciousness then splitted itself into multiple Jiva.
The equivalent of Jiva in english is perhaps the word "Soul" or in Arabic "Ruh".
Every Soul/Ruh contain Atman / Consciousness / Nafs inside.
The Soul/Ruh/Jiva is contained through something that's refer as "Karmic Structure".
Through "Karmic Structure" each Soul/Ruh/Jiva become finitely defined.
Through "Karmic Structure" the Atman is no longer ultimate, no longer boundless, it has a border of identification. It's then able to identify "Me" and "Not Me", "Me" and "You/He/She/It/Them".
Through "Karmic Structure" the Atman become "Separated" with each others.
This separated Atman is then labeled as Soul/Ruh/Jiva.
Yes every Soul/Ruh/Jiva is Atman thus also is Brahman.
The metaphor for this is: Air is the Atman and Bubble is a soul.
The wall of the bubble which separated the air inside a bubble with air in another bubble is the karmic structure.
The above is the framework explaining why "what you do to others, you actually doing it towards yourself".
Through "action" / "Karma", One bubble might be entangled with another bubble.
This is the metaphor of "Karmic Bondage" which bound one soul to another soul, one bubble to another bubble.
The bond can be 'positive' based on love or 'negative' based on hatred/revenge or other negative emotions.
This is where "Forgiveness" comes in.
Forgiveness is a manifestation of love/compassion.
Which can balanced out the manifestation of hate/fear/revenge thus break/neutralize the karmic bondage between soul.
This is the basic framework on the recommendation of "Forgive others as you would like to be forgiven".
As "others" is actually you as well, a part of you who are temporarily separated in different bubble, separated by Karmic Structure.
This karmic structure by itself is temporary.
Through love/compassion one bubble begin to merged with another.
Forming a bigger bubble.
As the bubble gets bigger, the karmic structure will become thinner.
As the karmic structure become thinner it will be easier to break.
Once the karmic structure has been broken, the contained / bordered air (Atman) inside the bubble (soul) will merge with the all ever Atman, with the all ever infinite air. Ending the lifecycle of a bubble or soul.
It's not a coincidence why the arabic word is "Nafs" as Nafs literally means Breath thus Air, as the closest metaphor.
This is what's being labeled as the state of "Mokhsa" (Liberation) or "Nirvana" (Blissful state) in Buddhism, the state of "No more Karma".
Jesus also explained the same state using the metaphor of "A son returning home to his Father" a.k.a "Parable of the Prodigal Son". The son coming back home seeking forgiveness of his father, and of course his father happily forgive his lost son. Why? Because the son is part of the father and between them there's always an everlasting bond of love. This is the ultimate destination of every soul/jiva/ruh; to return 'home' after experiencing 'temporary separation'.
What will remain then? Since the air/nafs/consciousness previously contained in a bubble/soul/jiva/ruh has merged back and no longer exist in separation?
What remains is the information / data of every action/event/karma as experienced by the separated nafs/consciousness inside a soul, neatly stored in universal cloud database labeled as "Akashic Record".