Do you think that you could enter paradise unless God takes cognizance of your having striven hard [in His cause], and takes cognizance of your having been patient in adversity?
Al-Imran (The Family of Imran) Verse 142
The Prophet said, "A faithful believer to a faithful believer is like the bricks of a wall, enforcing each other." While (saying that) the Prophet clasped his hands, by interlacing his fingers.
Sahih Bukhari: Volume 1, Book 8, Number 468