What is the ruling on kissing the hand? And what is the ruling on placing the hand on the forehead?

The Shaykh : The fifth question here: Kissing the hand?
We have also spoken about this question repeatedly, both in writing and in lectures; therefore, we will say briefly: The best state regarding kissing the hand is that it is said to be permissible, but with restrictions and conditions. The first of these is that it is used only with people of knowledge and virtue. There is no kissing of the hand for anyone other than scholars. There is no kissing of the hand in the greeting or touching of parents. There is no kissing of the hand for a Shaykh of a Sufi order or the like, who has nothing to do with knowledge. Kissing the hand is only reported regarding scholars, starting from the Messenger (peace be upon him), and secondly, from some of the Companions to some of them only. Then, it is not befitting for the followers and adherents of these scholars to make kissing their hands their constant habit and custom, but rather only occasionally, in a rare manner. And as I say, using the Syrian expression, it is from the category of "satisfying a desire" or "quenching thirst." A person loves another, and his eyes fall upon him, so he rushes to him and kisses his hand. There is no harm in this, but this is not a duty. The duty of meeting is not that whenever the student meets his teacher, or the seeker meets his Shaykh, he rushes to his hand and kisses it. No, rather, as we said, this is from the category of quenching longing and satisfying it.
As for the duty, it is what the Messenger (may Allah's prayers and peace be upon him) was upon, whose hand was kissed in incidents that do not exceed the number of fingers on one hand. Moreover, many of them are not authentic from the perspective of hadith narration. The total reported from this gives the careful, verifying researcher that his hand (peace be upon him) was kissed; how many times in his life? All the incidents are four or five, some authentic and some not. This was not a methodology from him (peace be upon him), nor a duty of his Companions with him. As for the duty, it was as some of his Companions said: "We never met the Messenger of Allah (may Allah's prayers and blessings be upon him) except that he shook hands with us." That is the duty. "We never met him (may prayers and peace be upon him) except that he shook hands with us." So, whoever is truly a person of knowledge and a person of following and emulating the Sunnah of the Messenger (peace be upon him) sincerely, he does what he (peace be upon him) did. The predominant practice between him and his Companions and followers is handshaking. He is like his other Companions, some with others; when they meet, how do they greet each other? First of all, "As-salamu alaykum," the greeting of Islam, then handshaking. This is what every Muslim does with his Muslim brother, and this is what the earliest Muslims, the Companions of the Messenger (peace be upon him), did with their Prophet (may Allah's prayers and peace be upon him). "We never met him except that he shook hands with us." This is the duty. So, whoever is as we described, he emulates the Messenger (peace be upon him) in this. If it occurs to one of them...
...the Sunnah. As for extending the hand, while the Messenger never extended it, and it was taken from him against his will, this is a contradiction of the Messenger (peace be upon him). Whoever does this is contradicting the Messenger (peace be upon him). And if someone argues with you that this is a Sunnah, we say to him: You have lied. The Sunnah is that a person comes with a longing boiling in his chest like a cauldron, and he wants to extinguish this heat from his belly, so he rushes to his Prophet (may Allah's prayers and blessings be upon him) and kisses his hand. This is the Sunnah. As for you, saying this while people pass by in rows, one... this is not of the Sunnah at all, absolutely. Rather, this is an improper and unclean exploitation of some hadiths that occurred in the rare instances of the relationship between the Messenger (peace be upon him) and his Companions.
This is what can be said regarding this question.

The questioner : Placing the hand on the forehead?

The Shaykh : This has no basis at all, and this is an exaltation of a means specific to placing the forehead on the ground for Allah, Lord of the worlds, only.