Is it permissible for an employee to accept a gift (a string of prayer beads) from someone for whom he completed a transaction, knowing that the employee completed the transaction as he would any other and was not expecting a gift, but he welcomed the person warmly due to his colleague's standing?

What is given to an employee for his work falls under the category of gifts to workers, and it is not permissible to accept it except with the permission of the employer, due to the Prophet's (peace be upon him) saying: "Gifts to workers are ghulūl (illicit gain)," and his saying to the one who was given a gift while he was working as a zakat collector: "What is wrong with a worker whom I send, and he says: 'This is for you, and this was gifted to me'? Why did he not sit in the house of his father or in the house of his mother to see if he would be given a gift or not?" This is unless the gift is from a friend or someone accustomed to giving him gifts before his employment.