But the fighting did not stop and in fact, seemed to intensify.

Aerial bombardment continued, supporting Israeli forces trying to get as close as possible to the centre of Gaza City before the truce.

Hamas fighters set up ambushes to incapacitate as many tanks and armoured personnel carriers as possible before the ceasefire stops all military activity for 96 hours.

The last two days must have been the most nerve-racking for fighters on both sides since the beginning of the ground campaign.

Military historians have written volumes on the simultaneous anxiety, stress, expectation, hope, mental pressure and existential fear of soldiers in the hours before a ceasefire or truce.

In all wars, wherever and however they are fought, no soldier wants to be the last casualty before the guns go silent. As they hear the news of the imminent pause, their natural reaction is to relax, ease the efforts, for soon they are to stop all activity.

Rather than allowing that, their officers – following orders and pressure from their respective civilian authorities – push them to press on for another day, two or three. Soldiers, themselves unit commanders, hate to have to do it, knowing what effect such orders have on troop morale, but they cannot disobey their superiors.

That tense anticipation of the Zero Hour when they will, at least temporarily, lay down their weapons, is almost certainly the most stressful time of their military career.

Civilian authorities certainly must know this, so why have they allowed Zero Hour to slip to 7am on Friday, prolonging the agony of their own soldiers?

Some of it is just civilian officialdom. An alleged reason that postponed the pause was that the agreement was not formally signed by Qatar and Hamas, “only officially announced”. More red tape was involved in “clarifying the names on the lists of those to be released”. All those seemingly unnecessary obstacles delayed the start of the pause.

In all fairness, the bureaucracy is not the only thing to blame for the slow implementation of the agreement, it is just the most visible, but military commands were not rushing either.

For the truce to work, it must be made workable in the first place. Politicians agree in broad terms: “Let’s pause the fighting and exchange people”. The wording defines intent and scope, but exactly how to implement what has been agreed upon always falls to those on the ground: the military.

It is not an easy task: Officers of two enemies who have been trying to kill each other now have to talk – as fighting rages.

I have seen many ceasefires and prisoner exchanges, but do not remember a single one where a political agreement signed by big bosses could be implemented without the adversaries on the battleground working out the fine print, for the devil is always in the detail.

To start with, some officers are chosen to study the agreement and, knowing the situation on the battlefield, determine how they will carry it out. They need to decide viable, safe routes for the buses taking hostages and prisoners from one side to another, agree if the buses will have civilian or military drivers and possibly guards, decide if guards would be armed or not.

Will they be accompanied by medical personnel? At what point will they be released or transferred from one set of buses to another?

Will any soldiers participating in the exchange cross into enemy territory, and, if so, when and how will they return? Who’s responsible for clearing the roads of rubble and mines and to what point? And many more sticky, difficult issues.

Establishing first contact is easier than most people think: The adversaries listen to each other’s radio communications and often use the same walkie-talkie channels. In moments of relative calm, they will taunt each other: boasting, threatening, insulting, belittling, cursing … But after the pause was announced someone certainly called the other side and said: “My commander wants to talk to your commander about the truce.”

First, they need to confirm their authority, then start arranging an initial consultation, usually with both sides promising to keep the proposed meeting place safe and agreeing on how many negotiators and aides would meet face to face.

The moment the opposing envoys first meet is the tensest, as any seemingly trivial detail can collapse the whole deal. Who will salute first? What happens if one representative declines to shake the other’s hand? Does an Israeli officer give a military salute, given that for the Israeli side, the opposite number is a “terrorist”? What happens if they cannot agree on some issues?

With so many potential traps, the two sides often prefer to use an intermediary they trust to can help clarify matters, defuse tensions and propose mutually acceptable solutions, a middle-of-the-road approach where neither negotiating side would lose face.

It helps if the intermediary knows the situation and has dealt with both sides in the past. In Gaza, that will be the International Committee of the Red Cross/Red Crescent (ICRC).

As announced by Qatar on Thursday, the first captives are to be released at 4pm on Friday, just nine hours after the fighting is supposed to stop. That suggests that most details I listed here have already been ironed out, and that gives reason for cautious optimism.

The only slight doubt in my mind is the practicality and wisdom of starting an exchange of civilians at a time when the darkness is starting to set in. Conducting any business after the sun sets is never a very good idea in a combat zone.