We ask Allaah to bless this new house for you and to make it a haven of righteousness, goodness and blessing. 

I will tell you what it is prescribed for you to do and say: 

Firstly: 

Be grateful for the blessing of Allaah, for gratitude is one of the noblest of attitudes. 

Ibn al-Qayyim said in Madaarij al-Saalikeen (2/242): 

Faith is of two halves: half is gratitude and half is patience. End quote. 

If a person is grateful to his Lord, He will preserve His blessing to him and complete it, and increase it and others. 

Allaah says (interpretation of the meaning): 

“And (remember) when your Lord proclaimed: If you give thanks (by accepting Faith and worshipping none but Allaah), I will give you more (of My Blessings); but if you are thankless (i.e. disbelievers), verily, My punishment is indeed severe”

[Ibraaheem 14:7]

Secondly: 

Make food and invite people to come and eat, for that is a way of showing gratitude to Allaah.  

It says in al-Mawsoo’ah al-Fiqhiyyah (8/206): 

Holding a feast after acquiring property is mustahabb, like all kinds of feasts that are given on happy occasions or so as to ward off evil. It is called wakeerah. It is not as important as the wedding feast, and some of the Shaafa’is narrated two opinions as to whether it is obligatory, because after mentioning feasts, al-Shaafa’i said: that includes the wakeerah … and I do not grant a concession allowing one to neglect it. End quote. 

Thirdly: 

Ibn al-Qayyim (may Allaah have mercy on him) said in al-Waabil al-Sayyib (155-156): 

Allaah, may He be glorified and exalted, said in the story of the two men (interpretation of the meaning): 

“It was better for you to say, when you entered your garden: ‘That which Allaah wills (will come to pass)! There is no power but with Allaah!’ If you see me less than you in wealth, and children”

[al-Kahf 18:39]

The one who enters his garden or house or sees something that he likes in his wealth or his family should hasten to say these words, and if he does, no harm will befall the thing that he admired. 

It was narrated that Anas (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “When Allaah blesses a person in his family, wealth or children and he says ‘Ma sha’ Allaah la quwwata illa Billaah (that which Allaah wills (will come to pass)! There is no power but with Allaah), he will not see any harm come to them before death.” 

Narrated by al-Tabaraani in al-Awsat (6/126); classed as saheeh by Ibn al-Qayyim in Shifa’ al-‘Aleel (1/182); classed as da’eef by al-Albaani in al-Silsilah al-Da’eefah (2012).

 And it was narrated that when the Prophet (peace and blessings of Allaah be upon him) saw something that he liked, he would say: “Al-hamdu Lillaah illadhi bi ni’matihi tatimmu’l-saalihaat (Praise be to Allaah by Whose grace good deeds are completed).” 

Narrated by Ibn Maajah (3803). Al-Nawawi said: Its isnaad is jayyid. Al-Adhkaar (399). End quote.

 Fourthly: 

It was narrated from Jaabir ibn ‘Abd-Allaah (may Allaah be pleased with him) that he heard the Prophet (peace and blessings of Allaah be upon him) say: “When a man enters his house, and mentions Allaah, may He be glorified and exalted, when he enters and when he eats, the shaytaan says: ‘You have no place to stay and no dinner.’ But if he enters and does not mention Allaah when he enters, the shaytaan says, ‘You have found a place to stay.’ And if he does not mention Allaah when he eats, he says: ‘You have found a place to stay and dinner.’” 

Narrated by Muslim (2018). 

This dhikr is not only for a new house, rather it includes all houses and all times of entering. So start your life in your new house with remembrance of Allaah, may He be glorified. 

Among the ways in which you may seek protection for your new house from the evil eye and destructive envy is to say: “U’eedhuka bi kalimaat-Allaah il-taammah min kulli shaytaanin wa haammah wa min kulli ‘aynin laammah (I seek refuge for you in the perfect words of Allaah from every devil and poisonous reptile, and from every envious evil eye).” 

Narrated by al-Bukhaari (3371). 

Fifthly: 

The Sunnah encourages reading Soorat al-Baqarah, especially in one’s home. 

It was narrated from Abu Hurayrah (may Allaah be pleased with him) that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: “Do not make your houses into graves, for the Shaytaan flees from a house in which Soorat al-Baqarah is recited.”

Narrated by Muslim (780). 

Shaykh Ibn Baaz (may Allaah have mercy on him) said in Majmoo’ al-Fataawa (24/413): 

It seems – and Allaah knows best – that by means of the reading of all of Soorat al-Baqarah, either on the radio or by the owner of the house, that which was mentioned by the Prophet (peace and blessings of Allaah be upon him) may be achieved, namely shaytaan fleeing from that house. End quote. 

However, we did not find any specific dhikr or du’aa’ to be said when entering a new house. 

And Allaah knows best.