وَإِذْ جَعَلْنَا الْبَيْتَ مَثَابَةً لِلنَّاسِ وَأَمْنًا
Remember We made the House a place of assembly for men and a place of safety
(Sūratul Baqarah, No. 2, Āyat 125)
The holy Kaaba is described in the above verse as:
1) A place of assembly or pilgrimage. The Arabic word used is ‘mathaba’ – a place of frequent return. People return to it often, worshipping God and reveling in the spirituality of the place. Apart from the physical return to the place, the word ‘mathaba’ also signifies a spiritual return to the original fitrah and purity of man.
2) A place of safety. Just like the home of a person is a place of frequent return and a source of peace and safety, the Kaaba also fulfills the same purposes. This is what the House of God should be for His creation. It is a place where they seek refuge and solace, both physically and spiritually. Visiting it gives peace to the visitors. Imam al-Baqir (a) has said, ‘Pilgrimage calms the hearts.’ [Amali al-Tusi, p. 296, no. 582]
The Kaaba attracts people from all corners of the globe. As soon as they reach Makkah, and witness the holy Kaaba with their own eyes, many are overwhelmed with emotion. They fall into prostration, forgetting the hardships of the journey. They recite: “O Lord of the House, the House is Yours and the servant is Yours.” Imam Ali (a) says about them; The people go to it as beasts or pigeons go towards spring water (Nahjul Balagha, sermon 1). The believer’s attraction to the House of God and the assembling of the Muslims for Hajj are great blessings bestowed by God.
For the Muslim Ummah, the Kaaba is a place where differences can be put aside. The belief in God and the greatness of the Kaaba overshadows any differences they might have. Unity of Muslims is the purpose of Hajj and the Kaaba is its central point. If carried out correctly, the rituals of Hajj increase the strength of the Muslims by making them join forces together.
Recite this verse as you turn towards the Qibla, envisioning the Kaaba and reminding yourself of its greatness and sanctity. It is a symbol of the attraction and centrality of God over the hearts.
Sources:
Aytaullāh Nāsir Makārim Shirazī (ed), Tafsīr Namūne,
Imam Ali (a), Nahjul Balagha
http://www.al-islam.org/hajj-the-islamic-pilgrimage-sayyid-mohammed-zia-abadi