On p. 232, Vol. 7, of Wasail al-Shi’a, and also on p. 69, Vol. 4 (old edition), of Al-Kafi, Imam Abu Ja’far al-Baqir (as) is quoted saying, "Do not say ‘this is Ramadhan,' or ‘Ramadhan has gone,' or ‘Ramadhan has approached,' for Ramadhan is one of the Names of Allah, the most Exalted, the most Great, and He neither comes nor goes; things that die come and go. Instead, you should say ‘the month of Ramadhan, for [in this case] the month will simply be identified, whereas the Name belongs to Allah, Exalted is His mention, whereas the month wherein the Qur'an was revealed is made by Allah a month for hopeful anticipation as well as of stern warnings."
Al-Majlisi quotes the same in his Bihar al-Anwar, citing Ibn Babawayh al-Qummi's Thawab al-A’mal wa ‘Iqab al-A’mal. Imam al-Baqir (as) here is simply repeating what the Messenger of Allah (S) had said as quoted by Imam Ali ibn Abu Talib, peace be upon him, thus: "Do not say ‘Ramadhan,' for you do not know what Ramadhan really is; instead, you should say just as the Almighty Allah has said in His Glorious Book ‘the month of Ramadhan,' and whoever says ‘Ramadhan' [only], let him both pay sadaqa (alms) and kaffara (atonement) so that his sin may be forgiven."1