A Muslim once insisted upon receiving a special piece of advice from the Holy Prophet (s). He (s) replied, ‘Do you pledge to act upon it if I do?’ ‘Certainly! Ya Rasool Allah.’
‘Are you sure you will act on it?’ ‘Absolutely! Messenger of God.’ ‘Do you promise to act on it?’ ‘I promise, Ya Rasool Allah.’
After repeating the question three times intentionally to make him realise the significance of the advice, the Holy Prophet (s) said: ‘Seriously evaluate the results of your action before performing it. If its end is good, perform it; if it can lead to deviation and ruin, abstain from it.’
Reference : Anecdotes of The Ahlul Bayt (Daastaan e Raastaan ) by Ayatullah Murtadha Mutahhari