In another narration, which Tabarani recorded, the wording is: "Whoever recites these words once (the narrator is in doubt; perhaps the wording is:) ten times, it will be for him equal to freeing one slave (the narrator is in doubt; perhaps the wording is:) ten slaves." The narrator is in doubt about both these words. The narrators of both narrations are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16821
Hadith Gradingمحدثین:إسنادہ صحیح
Hadith Takhrij«اخرجه الطبراني فى المعجم الكبير (4018)»