Fiqh-us-Sunnah Volume 3, Zakaat and Fasting, Fiqh 3.147.
Section : I’tikaf, its meaning.
I’tikaf means to stick to something, whether good or bad, and to block out everything else. Allah says in the Qur’an: “What then are images that you pay devotion [akifun] to them?” [alAnbia’ 52] – that is, what they devoted themselves to in worship. What is meant here is the seclusion and staying in the mosque with the intention of becoming closer to Allah.