Paul Schrader has never been one for subtlety, and in “First Reformed” his penchant for bludgeoning across a message is on full display, as is his characteristic Calvinistic rigor. But so is his ability to fashion a film that fascinates even as it goes wildly overboard.

The protagonist of “First Reformed” is Reverend Ernst Toller (Ethan Hawke), pastor at a small Dutch Reformed church in upstate New York that’s been preserved, despite a sparse congregation, because of its historical significance as a stop along the underground railroad. Toller is a deeply troubled man, a former military chaplain whose son died in the invasion of Iraq and feels guilt at having encouraged him to enlist; the boy’s death also led his wife to leave him. Toller secretly drinks, and is suffering from an undiagnosed stomach ailment, while pushing away the prim parish housekeeper (Victoria Hill), with whom he had apparently enjoyed an earlier relationship.

Given all this, it is hardly surprising that Toller’s freedom of action is being increasingly circumscribed by intervention from Pastor Jeffers (Cedric Antonio Kyles, better known as Cedric the Entertainer), who runs a nearby megachurch that treats Toller’s picturesque little establishment as a photogenic offshoot of his larger operation. Keeping things running smoothly is especially important given that Toller’s church is at the point of celebrating the 250th anniversary of its foundation, an event that will attract a good deal of attention in the press.

The celebration is, however, being funded by a questionable patron: Ed Balq (Michael Gaston), who runs a petroleum company that shows little concern for the impact of its operations on the environment. That fact will be brought home to Toller when he is approached by Mary (Amanda Seyfried), who asks him to meet with her husband Michael (Philip Ettinger), an activist who is convinced that the earth is becoming uninhabitable and shows every indication of readying himself to go to violent extremes in protest. The pastor’s embrace of Michael’s cause—and, as it happens, concern for his wife—will draw him to consider radical action himself.

Schrader’s debt to Bergman and Bresson (whose “Diary of a Country Priest” is an obvious influence) is apparent throughout “First Reformed,” not only in its austere, controlled style (the cinematography by Alexander Dynan mimics the sharpness and angularity of the church Toller presides over) but in its narrative form, in which the reverend records his experiences, thoughts and intentions in a journal whose entries, read by Hawke, drive the story forward. One has to admire the intensity with which the film grapples with the question of what a real embrace of the Gospel means in terms of personal commitment and action, as well as the need for meaningful personal connection in a callous world.

At the same time, however, the film—like Schrader’s others—is both deeply serious and unrestrained in its adoption of the elements of pulp melodrama. It goes for broke toward the close, setting up a scenario that combines the potential for explosive terrorism with a longing for self-flagellation, and adding to that mix a penchant for flamboyantly over-the-top imagery that becomes positively baroque (a style certainly out of sync with the architectural simplicity of Toller’s church).

What to make of this mixture of rigor and extravagance? One can say that while it might seem weird in almost any other director, it’s quite typical of Schrader, who has always combined the sublime with the ridiculous, and has been lucky enough to find collaborators willing to devote themselves to his very personal vision. This time around, his chief partner is Hawke, who delivers a performance that fully embodies Toller’s angst and despair. The character is a study in extremes, but Hawke manages to endow him with real humanity as well. Seyfried and Ettinger contribute effective if subdued support, and while Gaston goes for obvious obnoxiousness, Kyles provides a spot-on depiction of a pragmatic clergyman who might have grudging admiration for Toller’s devotion to the ideals of Thomas Merton, but is more concerned with getting along with Mammon than he is in upsetting the real-world applecart.

There’s no question that “First Reformed” is short on plausibility and restraint, but its willingness of take risks compels respect, even when it goes off the rails.