'Shall I not direct you both to something better than a servant? When you go to bed say:'

سُبْحَانَ اللَّهِ

How Perfect Allaah is.

Subhaanallaahi

….thirty-three times

وَالْحَمْدُ لِلَّهِ

All praise is for Allaah.

Walhamdu lillaahi

...thirty-three times

وَاللَّهُ أَكْبَرُ

Allaah is the greatest.

Wallaahu 'akbar.

...thirty-four times...for that is indeed better for you both than a servant.

Al-Bukhari, Fathul Bari 7/71, Muslim 4/2091.