[3:41] He said, 'My Lord! Appoint for me a sign'. He said, 'Your sign is that you shall not speak to men, save by tokens for three days.
He sought the sign so that he would know the time of the reply more precisely, not because of any doubt regarding the source of the replying. He made the sign of His proof the restraining of his tongue with created beings while loosening it with God in glorifying Him, i.e., 'Do not refrain from speaking with me for I do not deprive My friends of My intimate conversations (munājāt)'.
[3:41 cont'd] and remember your Lord often
In your heart and your tongue in every moment.
[3:41 cont'd] and glorify [Him] at evening and dawn'
In persistent prayer.