Verily, those who have attained to faith and do good works, and are constant in prayer, and dispense charity - they shall have their reward with their Sustainer, and no fear need they have, and neither shall they grieve.
Al-Baqara (The Cow) Verse 277
Allah's Apostle said, "If I had not found it hard for my followers or the people, I would have ordered them to clean their teeth with Siwak for every prayer."
Sahih Bukhari: Volume 2, Book 13, Number 12