My father hates being late.

If the invitation calls for a 7 p.m. start, he's standing at the entrance at 6:58, waiting for the doors to open. It's as if he's never heard of "Jewish mean time." It's irrelevant that he's the first one there, that the caterers are only just setting up; he knows that the function was supposed to begin at a certain time, and he doesn't want to be late.

Me? I'm not so punctual.

I should be. It's rude to be constantly late to meetings, apologizing, yet again, for your tardy arrival. I know that it bothers some of our minyan regulars that services always seem to begin a few minutes after the official kick-off time. It's not that I don't care, it's just that no matter how well intentioned I am, some distraction or emergency situation always pops up just when I should be heading out.

When G‑d makes a promise, He fulfils His word with accuracy and punctualityI'm getting better at it. I've learned to factor in travelling time before committing myself to an ETA. I try not to double-book events, and plan my schedule in advance. I accept that punctuality is a sign of respect, as well as evidence of good manners, and I hope to continue to improve as I age.

If I needed any encouragement, I can learn a lesson from the Torah reading of Va'eira. One by one, G‑d is visiting the ten plagues upon the hapless Egyptians. Blood, frogs and lice have come and gone. Wild animals have wreaked havoc, disease has infested the cattle and the Egyptians have been struck with boils. The day before bringing the seventh plague, hailstones, G‑d warns Pharaoh: "I am sending a plague… in order that you should know that there is none like Me in the entire earth… in order to show you My strength and thus declare My name over the entire earth… At this time tomorrow I will rain down a devastating Hail."

The sages explain that Moses scratched a line on the spot where the sun was hitting the wall. "At this time tomorrow," he warned, "twenty-four hours from now, at the exact moment the sun returns to this point, the plague will begin."

Of all the time-calculating methods available to the ancient Egyptians, this was the most accurate. Moses was prophesising the precise moment when they could expect the hailstones to begin, and G‑d duly carried out this threat.

The Torah is teaching us an elementary, yet essential, lesson. Of all the plagues, this one was intended to demonstrate G‑d's strength, power and presence. Integral to these Divine attributes is a commitment to punctuality and the obligation to keep one's word. When you promise to begin something at a certain time, near enough is not good enough; you've got to deliver with promptitude and carry through with precision.

When G‑d makes a promise, He fulfils His word with accuracy and punctuality. It is an obligation for us, who follow in His ways, to commit to nothing less.