The language quality of your research paper can determine whether it gets rejected or accepted for publication. Even if the quality of your science is exceptional, your research may never be published if the language is poor.
To improve your chances of being accepted for publication, a manuscript has to be mostly error-free and of a good standard of English. For example, Elsevier journals reject 30% to 50% of submitted articles before peer review. One of the main reasons for rejection is poor language quality.
Even native speakers of English can find it challenging to make sure the language used in a paper is of a high standard. It can be even more problematic if English is your second (or third) language. You can significantly improve your chances of getting published if you use a reputable editing service.