"Forever" was well received by professional critics, who made favorable comments towards the vocal performances, the contributions of the guest stars, sound and composition.

[4] On February 5, Bieber revealed the tracklist for Changes, which listed Malone and rising hip hop artist Clever as features on the seventh track titled "Forever".

[13] Lynn Sharpe from HotNewHipHop praised the vocals on "Forever", feeling that Bieber and Malone "compliment[ed] each other" in a seamless manner and that Clever beautifully reflected the track's "passionate nature".

[13] Billboard critic Taylor Weatherby ranked it as the third-best song on Changes and regarded it as "one of the most distinctive tracks" on the album, highlighting "[t]he plinking production, the staccato chorus, Post Malone's very Posty verse and Clever's punchy lines".

Club's Annie Zaleski felt it was one of Changes's "most enduring moments", adding that Malone and Clever bring "gruff vulnerability" to the song.

[19] Joshua Bote of Paste remarked that Malone "adds a frantic tension to the cut", but disapproved of Bieber as "sound[ing] drained".

[23] A dance visual for "Forever", directed by Nick DeMoura, was released on March 9, 2020, as part of a collection of 16 music videos titled Changes: The Movement.

[25] Straying away from the previous visuals for "Habitual" and "All Around Me" which focus on intimate and intricate routines, the video centers around a group of masked performers wearing riot gear-styled attire that dance as lights flicker around them.