And by this secure land.
The secure land refers to Mecca, where the Ka’ba, the first place of worship for mankind, is situated. Both before and after the deputation of Muhammed, who is the Mercy for the entire world as told in verse 21: 107, Mecca has remained a secure place — and will continue so until the Last Day. That is because the security of the Ka’ba is undertaken by the Lord of the Universe Himself.
The Lord has taught through His Messenger that in the last period, Real Islam will withdraw into Hejaz (the province including Mecca and Medina) just as a snake withdraws into its hole. As explained in verse 48: 6, by the coming of Imam Mahdi, all believers from different parts of the world will be gathered in Hejaz, and the Fujjar will be expelled from there. See explanation 3: 96; 42: 7.