that the Messenger of Allah (ﷺ) said: "From the complete of visiting the ill is that one of you place his hand on his forehead" - or he said - "on his hand, and ask him how he is. And shaking hands completes your greetings among each other."
Jami` at-Tirmidhi Book 42, Hadith 44
← Previous Hadith that the Prophet (ﷺ) said: "taking hold of the hand is from the completeness of the greeting."

Jami` at-Tirmidhi Book 42, Hadith 43 Next Hadith → "Zaid bin Harithah arrived in Al-Madinah while the Messenger of Allah (ﷺ) was in his house. So he went and knocked at the door, so the Messenger of Allah (ﷺ) stood naked (1), dragging his garment - and by Allah! I did not see him naked before nor afterwards - and he hugged him and kissed him."

(1) They say that the meaning of naked here is that he was not wearing his Rida or upper wrap and it was that which was dragging, so the area between the navel and knees were covered. See Tuhfat Al-Ahwadhi.

Jami` at-Tirmidhi Book 42, Hadith 45