Are the Five Precepts a gradual training?

Question

In this answer it's said that the Five Precepts are not a form of gradual training.

Are they are a gradual training? If not, why?

Thank you for your time.

Answer 1

The five precepts are not a gradual training. Buddhists undertake it as the most minimum training in virtue (sila).

Followers of Buddhism are expected to undertake the training in the five precepts mindfully (i.e. keeping it in mind) with right effort.

If they lapse, they should continue to try their best the next time, without feeling remorse, as this is a voluntary training and not divine commandments.

What might be gradual is the degree of perfection of the practice of the five precepts. This is not strictly required for lay persons, but it is definitely expected of monks and nuns.

Here's the sutta stating the expectation on monks to practise perfection in virtue.

"And how is a monk consummate in beauty? There is the case where a monk is virtuous. He dwells restrained in accordance with the Patimokkha, consummate in his behavior & sphere of activity. He trains himself, having undertaken the training rules, seeing danger in the slightest fault. This is how a monk is consummate in beauty.
AN 3.94

For e.g. you may avoid killing humans and most animals, but you may occasionally kill mosquitoes or house pests intentionally. Striving for perfection in the undertaking of the first precept means not causing the death of any sentient being at all.

You may not steal or take what is not given, but you may occasionally park illegally when you are not able to find legal parking available, and you may get away with it without getting a parking ticket. Striving for perfection in the undertaking of this precept means never parking illegally. Please also see this answer.

You may not drink alcoholic beverages till you become drunk and heedless, but you may drink a little occasionally for social reasons. Striving for perfection in the undertaking of this precept means never recreationally consuming any intoxicating substance at all, even a little.

You may not have a sexual and/or romantic relationship or fling with anyone who is not in a mutually exclusive long term relationship with you, but you may occasionally mildly flirt with someone other than your exclusive long term partner. Striving for perfection in the undertaking of this precept means never engaging in a flirtatious manner with anyone who is not your exclusive long term partner (should you have one).

And what about the precept of not speaking untruth?

Well, you should try to practise it to perfection, even as a lay person. The reason for this is explained below.

This was said by the Blessed One, said by the Arahant, so I have heard: "For the person who transgresses in one thing, I tell you, there is no evil deed that is not to be done. Which one thing? This: telling a deliberate lie."

The person who lies,
who transgress in this one thing,
transcending concern for the world beyond:
there's no evil he might not do.
Iti 25

Answer 2

There are many suttas that say merely transgressing one of the precepts leads to a bad outcome. For example, if you keep the four precepts but not the 3rd, this won't stop your spouse divorcing you; or if you keep four precepts but not the 1st, those won't stop you being imprisoned for murder.

For example, imagine being a strict moralist about not stealing, not engaging in sexual misconduct, not lying and not taking drugs & alcohol; and therefore you go around executing (killing) people who transgress these four precepts. Keeping four precepts won't protect you from the repercussions of killing others.