Let him who is without vice...
... give the first advice.
Like I said, I've never quite been of that school of thought.
Especially when it comes to advice rather than stones.
And I believe that if you insisted on that principle when it comes to giving medical advice, many doctors will have awfully little to say to their patients.
Here are the numbers:
There are about 6500 doctors in Singapore. Let's say 5000 are male, and 1500 female.
Now given that 24.9% of men and 4.1% of women in Singapore smoke, that makes (assuming the ratio applies to doctors) about 1300 smoking doctors.
And 784 doctors who drink regularly or frequently.
And 2200 doctors who are overweight.
If they were the same doctors (i.e. the smoker is also a drinker and overweight), you have at least 2200 doctors who are disqualified from giving advice against these 'vices'.
If they were all different doctors (i.e. doctors only ever smoke, drink, or are overweight - an unlikely scenario), you end up with almost 4300 doctors who are 'into vices'!
In other words, if you assume that doctors are not more immune to vices than the average person, fully a third to two-thirds of us are disqualified from giving 'healthy lifestyle' advice.
So where does that leave us?
To milk the religious theme further, I would say it's a matter of whether you expect your doctor to be a saint who gave you the message through his viceless living, or an angel who is just here to give you the message. Whichever the case, at the end of the day you must remember it's really between you and God.
I'm no saint, but I have been called the Angel of Death.