Taking care of the mosques and tidying the furniture etc inside them is something that is praiseworthy and encouraged. The one who does that will be rewarded by Allaah for this good deed.
Allaah has commanded us to venerate the mosques as He says (interpretation of the meaning):
“In houses (mosques) which Allaah has ordered to be raised (to be cleaned, and to be honoured), in them His Name is remembered [i.e. Adhaan, Iqaamah, Salaah (prayers), invocations, recitation of the Qur’aan]. Therein glorify Him (Allaah) in the mornings and in the afternoons or the evenings,
Men whom neither trade nor sale (business) diverts from the remembrance of Allaah (with heart and tongue) nor from performing As-Salaah (Iqaamat-as-Salaah) nor from giving the Zakaah. They fear a Day when hearts and eyes will be overturned (out of the horror of the torment of the Day of Resurrection)”
al-Suyooti said: In this verse there is the command to venerate the mosques and cleanse them of idle talk and impure things. From Tafseer al-Qaasimi, 12/214
Another sign that points to the virtue of the one who takes care of that is the report in al-Saheehayn from the hadeeth of Abu Hurayrah, that a black man or a black woman used to take care of the mosque, then he or she died. The Prophet (peace and blessings of Allaah be upon him) asked after him (or her) and was told that he had died. He said: “Why did you not inform me? Show me his grave (or her grave).” Then he went to the grave and offered the funeral prayer over it.” Narrated by al-Bukhaari, 458; Muslim, 956.
And it was narrated by Abu Dawood (455), al-Tirmidhi (594) and Ibn Maajah (759) that ‘Aa’ishah said: The Messenger of Allaah (peace and blessings of Allaah be upon him) commanded that mosques be built among houses and that they be cleaned and perfumed.” Classed as saheeh by al-Albaani in Saheeh al-Tirmidhi, no. 487.
What is meant by “among houses” is in neighbourhoods and among tribes.
The Prophet (peace and blessings of Allaah be upon him) regarded spitting in the mosque as a sin and said that the expiation for that was burying it. In al-Saheehayn it is narrated that Anas said: The Messenger of Allaah (S) said: “Spitting in the mosque is a sin and its expiation is burying it.” Narrated by al-Bukhaari, 415; Muslim, 552.
Al-Nasaa’i (728) and Ibn Maajah (762) narrated from Anas that the Prophet (peace and blessings of Allaah be upon him) saw some sputum in the qiblah of the mosque and he got so angry that his face turned red. Then a woman from among the Ansaar came and scratched it and put some perfume in that place. The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “What a good deed this is.” This hadeeth was classed as saheeh by al-Albaani in Saheeh al-Nasaa’i and Saheeh Ibn Maajah.
And it was proven that the Prophet (peace and blessings of Allaah be upon him) removed that himself as was narrated in al-Saheehayn where it says that ‘Aa’ishah said: “He saw some sputum on the wall of the mosque and scratched it off.” Narrated by al-Bukhaari, 407; Muslim, 549.
And there are da’eef ahaadeeth narrated concerning that which we will quote here only in order to explain that they are weak. In the saheeh reports from the Prophet (peace and blessings of Allaah be upon him) there is sufficient evidence that we have no need of the weak reports.
Abu Dawood (461) and al-Tirmidhi (2916) narrated the hadeeth, “I was shown the rewards of my ummah for different deeds, even a speck of dirt that someone removes from the mosque.” This hadeeth was classed as da’eef by al-Albaani in Da’eef al-Tirmidhi.
Ibn Maajah (757) narrated a hadeeth, “Whoever removes anything harmful from the mosque, Allaah will build for him a house in Paradise.” This hadeeth was classed as da’eef by al-Albaani in Da’eef ibn Maajah.
With regard to looking after the imam, Imam Muslim said in the introduction to his Saheeh:
“The man of high status should be given the respect to which he is entitled, and the one who has a low level of knowledge should not be elevated above his status. Every person should be given his due (of respect) and should be honoured in accordance with his status. It was narrated from ‘Aa’ishah (may Allaah be pleased with her) that she said: The Messenger of Allaah (peace and blessings of Allaah be upon him) commanded us to give people due respect.”
If the imam is a person of virtue, knowledge and righteousness, then love for him comes under the heading of loving and respecting the righteous. This is a righteous deed.
But it should be noted that the matter should not be allowed to go to the extreme of seeking blessing (barakah) from the imam or touching him (for the purpose of seeking blessing) as some people do, for this is not part of the teaching of the earliest Muslims, either their imams or their scholars.
And Allaah knows best.