Imperfect Blessings

Imam ar-Ridha (a) said: “He who fails to expiate his sins should give much of the blessings for Mohammed and his family, for they destroy the sins.”
The Prophet (s) said: “Do not utter the imperfect blessings for me.”
They asked: “What is the imperfect blessings?”
He answered: “The imperfect blessings is to say ‘Lord, bless Mohammed,’ and keep silent. You must say, ‘Lord, bless Mohammed and the family of Mohammed.’”Fadhaail ul-Khamsa min as-Sihah is-Sitta. (This narration is recorded in as-Sawaaiq ul-Muhriqa; page 87) ) 

Reference :The Ahl Ul-Bayt Ethical Role-Models