Ramadan is the month of the disobedient (those who rebel against Allah), as it is the month in which they are offered the opportunity for forgiveness.
Dhū al-Nūn al-Miṣrī says: Rajab is so named because calamities are abandoned in it; Shaʿbān because obedience is performed in it; and Ramadan because karāma (a saintly wonder) is expected in it. Whoever does not abandon calamities, does not perform acts of obedience, and does not expect karāma, is among those who indulge in pleasure and amusement.
He also says: Rajab is the month of sowing, Shaʿbān is the month of irrigation, and Ramadan is the month of harvesting what has been sown. Everyone reaps what they have sown and receives the recompense for their deeds. Whoever has not sown seeds will feel regret at harvest time and, being resurrected in a bad state, will have their assumptions and opinions about the dunya (this world) changed. (Gunya, 178)
The word Shaʿbān consists of five letters: shīn, ʿayn, bāʾ, alif, and nūn. Shīn stands for honor; ʿayn for loftiness; bāʾ for birr (goodness); alif for intimacy; and nūn for nūr (light). All these gifts are bestowed upon the servant by Allah during this month. It is a month in which goodness is opened, blessings descend, errors are abandoned, evils are concealed, and salawāt (invocations of blessings upon the Prophet) are increased. This is the month of sending salawāt upon the Prophet five times. (Gunya, I, 188)
According to the narration of Asmaʿī from Abū ʿAmr, the month is called Ramadan because, during Ramadan, camel calves become very hot due to the heat. Others say it is so named because stones become intensely heated by the sun during this month. Those who say it is called Ramadan because sins are burned in this month attribute this to a narration from the Prophet (peace and blessings be upon him) (Daylamī, II, 356).
It is also said: Just as sand and pebbles are heated by the sun, so too do hearts receive admonition and reflection about the Hereafter from the fire.
The famous lexicographer Khalīl Aḥmad says: Ramadan takes its name from the word ramaḍ, which refers to the rain that falls in autumn. The month is called Ramadan because, just as rain cleanses everything, it completely purifies sins and cleanses the qalb (the heart). (Gunya, II, 5)
recebiyyūn (those of Rajab): They are always forty in number, neither increasing nor decreasing. They are men who are constantly in qiyām (standing in prayer) due to the majesty of Allah... (Futūḥāt, II, 11; Nabhānī, I, 40) ...They are people who possess the 'weighty word' (qawl thaqīl). The 'weighty word' is what Allah refers to in the verse: "We will cast upon you a weighty word" (al-Muzzammil 73:5). (Futūḥāt, II, 11)
They are called recebiyyūn (men of Rajab or those belonging to Rajab) because they maintain these states during the month of Rajab. From the moment the crescent of Rajab is sighted until the end of the month, they persist in this state of qiyām. Afterwards, they lose this state and do not experience it again until the next Rajab. Very few from among the people of this path know them. They are scattered throughout the land and recognize each other. Some of them are in Yemen, Syria, and Diyarbakır. (Nabhānī, I, 40)