Meaning of the hadith “No haamah and no Safar and no naw’ and no ghoul”
Question

I read a strange hadith which says that there is no haamah, no Safar, no naw’ and no ghoul. What do these words mean?
Praise be to Allah.Ibn Muflih al-Hanbali said: 
In al-Musnad, al-Saheehayn and elsewhere it is narrated that the Prophet (peace and blessings of Allah be upon him) said: “No haamah and no Safar.” Muslim and others add the words, “No naw’ and no ghoul.” 
Haamah (pl. Haam) [owl]: the people of the jaahiliyyah used to think that when someone died and was buried, an owl [haamah] would come out of his grave. The Arabs used to think that the bones of the deceased turned into owls which flew, and they said that if someone was murdered, an owl would come out of his head, and it would keep saying, “Give me to drink, give me to drink,” until the slain person was avenged and his killer was killed. 
Safar: it was said that they used to have superstitions concerning the month of Safar, so the Prophet (peace and blessings of Allah be upon him) said: “No Safar”. And it was said that the Arabs used to believe that there was a snake in the stomach which would harm a person when he had intercourse, and that this was contagious, so the Lawgiver denied that. Maalik said: the people of the Jaahiliyyah would regard Safar as not being sacred one year and as sacred the next year. 
Naw’: (pl. al-Anwaa’) (a star which sets at the rising of another): this refers to twenty eight lunar mansions or phases, as in the aayah (interpretation of the meaning): 
“And the moon, We have measured for it mansions…”[Yaa-Seen 36:39].  
Every thirteen nights, one of these stars sets in the west at dawn, and another rises in the east, so that at the end of the year they will all have come and gone. The Arabs used to believe that when one set and the next one rose, there would be rain, which they attributed to them (these stars), so they would say, “We have rain because of such and such naw’ (star which sets at the rising of another).” 
It is called naw’ because when the star which is setting sets in the west, the one which is rising appears (naa’a) in the east, i.e., it rises and emerges. And it was said that naw’ means setting, which is the opposite. 
But in the case of those who believe that rain came by the will of Allah and say, “We have rain at the time of such and such naw’” meaning that Allah usually causes rain to come at this time – there is some dispute as to whether saying this is haraam or makrooh. 
Ghoul (pl. gheelaan) means a kind of jinn or devil. The Arabs used to think that the ghoul lived in the wilderness and would appear to people, and that it could take on different shapes and colours, and that it would make them lose their way, seeking to kill them. The Lawgiver rejected and denied this idea altogether. 
And it was said that this was not denying that ghouls exist, rather it was a denial of the Arabs’ belief that they could change shape and colour and make people lose their way, hence the meaning of “no ghoul” is that they cannot make people lose their way. This is borne out by another hadith, “There is no ghoul but there is sa’aali” This is in Muslim and elsewhere. Sa’aali is a magician among the jinn, but among them there are magicians who base their magic on confusion and illusions… al-Khallaal narrated from Taawoos that a man accompanied him, then a crow cawed and the man said, “Good, good.” Taawoos said to him, “What good is there in this, and what evil? Do not come with me!” 
(al-Aadaab al-Shar’iyyah, 3/369, 370) 
Ibn al-Qayyim said: 
Some scholars said that the words “no healthy person should be exposed to a sick person” were abrogated by the words “There is no ‘adwa (contagion).” This is not correct. This is an example where what is negated is different than what is affirmed. What the Prophet (peace and blessings of Allah be upon him) denied when he said “There is no contagion and no Safar” was the belief of the mushrikeen which was based on their beliefs of shirk. With regard to the Prophet’s prohibition of exposing healthy people to sick people, there are two interpretations: 
(1) The fear that people may attribute what Allah has decreed to ‘adwa (contagion), which may confuse those who hear of this and make them believe in ‘adwa. There is no contradiction between the two reports.
(2) That this refers to exposing the sick person to the healthy person, which may be the means by which Allah creates disease, so the exposure is the cause, but Allah may divert its effects by means of other causes which oppose it or prevent the effect of the sickness. This is pure Tawheed, unlike that which the people of shirk believe in. 
This is similar to the denial of intercession on the Day of Resurrection mentioned in the aayah (interpretation of the meaning): 
“when there will be no bargaining, nor friendship, nor intercession”[al-Baqarah 2:254] 
This does not contradict the unambiguous mutawaatir ahaadeeth which say that there will be intercession on the Day of Resurrection, because what Allah is denying here is the kind of intercession that was known among the mushrikeen, where an intercessor would come forward and intercede without being given permission. The intercession which is affirmed by Allah and His Messenger is that which comes after His permission is given, as in the aayahs (interpretation of the meaning): 
“…Who is he that can intercede with Him except with His Permission?…”[al-Baraqah 2:255] 
“and they cannot intercede except for him with whom He is pleased”[al-Anbiyaa’ 21:28] 
“Intercession with Him profits not except for him whom He permits”[Saba’ 34:23] 
Haashiyat Tahdheeb Sunan Abi Dawood, 10/289-291) 
And Allah is the One Who grants strength to do what is right.