Is the intention of entering the state of ihram in the verbalization with the tongue?

Question: Is the intention of entering the state of ihram in the verbalization with the tongue, and what is its nature if the pilgrim is performing Hajj on behalf of another person?

Answer: The place of the intention is the heart, and its nature is that one intends in his heart that he is performing Hajj for himself, or for so-and-so, or for his brother, or for so-and-so the son of so-and-so. This is how the intention is made. It is recommended (mustahabb) along with this to verbalize it and say: "O Allah, here I am responding to You for Hajj on behalf of so-and-so," or "Here I am responding to You for 'Umrah on behalf of so-and-so," or on behalf of his father, or on behalf of so-and-so the son of so-and-so, in order to confirm what is in the heart with the words. This is because the Messenger of Allah (peace and blessings be upon him) verbalized the Hajj and verbalized the 'Umrah, which indicates the lawfulness (shar'iyyah) of verbalizing what one intends, following the example of the Prophet (peace and blessings be upon him). Likewise, the Companions verbalized it as their Prophet (peace and blessings be upon him) taught them, and they raised their voices with it. This is the Sunnah.
If one does not verbalize it and is content with the intention, the intention suffices. He performs the acts of Hajj just as he does for himself. He recites the talbiyah absolutely and repeats the talbiyah absolutely without the need to mention so-and-so or so-and-so, just as he recites it for himself, as if he were a pilgrim for himself. However, if he specifies the person in the ritual, it is better in the talbiyah. Then he continues with the talbiyah like the other pilgrims and those performing 'Umrah: "Here I am, O Allah, here I am. Here I am, You have no partner, here I am. Indeed, praise and blessing are Yours, and dominion. You have no partner. Here I am, O God of Truth, here I am."
The point is that he recites the talbiyah just as he does for himself, without mentioning anyone except at the beginning of the ritual. He says: "Here I am for Hajj on behalf of so-and-so," or "Here I am for 'Umrah on behalf of so-and-so," or "Here I am for 'Umrah and Hajj on behalf of so-and-so." This is the best at the very beginning when he enters the state of ihram, along with the intention.