The Friday Gospels, By Jenn Ashworth. Sceptre, £17.99

In a crucial scene towards the end of Jenn Ashworth's remarkable new novel, a Mormon Bishop enjoins the homecoming missionary to conceal his sense of failure, when testifying to the congregation: "I'm just asking you to look at things in the best possible way. And to help other people to do that too." During his two years' away, the missionary, Gary, has failed to convert a single person to the Church of Latter-Day Saints, but the Bishop claims that: "What the ward is after is inspiration, not a list of facts and figures."

Inspirational testimony is, by this definition, selective. After Gary declares that he "can't do anything except tell the truth," the Bishop responds by saying: "Yes, but you can emphasise the most important aspects." According to the Bishop, testifying to religious "truth" means emphasising only the spiritual, uplifting and "important aspects" of experience, but Gary worries that by not saying everything, he is being dishonest.

In this sense, Ashworth's novel is strangely closer to Gary's model of truth than the Bishop's. The main characters – all from the same Mormon family – bear witness to their experiences over a day, revealing everything. Each chapter is structured as a pseudo-religious testimony from one of the family members.

As one character suggests, it ranges over a "whole gamut" of emotions, from "spitty sobbings and nose blowings to silent, dignified overflowing". It ranges over a whole gamut of thoughts as well: over the day, the narrators are variously contemplating, on the one hand, the efficacy of prayer, the value of friendship, the nature of miracles, and, on the other, pregnancy, suicide, escape, debt, infidelity, abduction.

Ashworth's characters are divided souls, with one foot in heaven, one on earth. At one point, one character, spying on another, observes the mother "pointing ... at the ceiling". "She could be talking about God or loft insulation," he thinks – and the poignant truthfulness of Ashworth's novel inheres in its ability to encompass and appreciate the significance of both.