Adam Clarke on Psalms 41:6

And if he come to see me - This may relate to Ahithophel; but it is more likely that it was to some other person who was his secret enemy, who pretended to come and inquire after his health, but with the secret design to see whether death was despatching his work.

When he goeth abroad, he telleth it - He makes several observations on my dying state; intimates that I am suffering deep remorse for secret crimes; that God is showing his displeasure against me, and that I am full of sorrow at the approach of death.