Experience has revealed that the emotions of the great personalities towards their children diminish due to the accumulation of activities and the increase of interests and concerns because the great goals and global concerns occupy their minds and thoughts to the point of extinction that leaves no space for their emotional feelings to appear and manifest. However, the great spiritual and moral personalities are excluded from this rule. With what occupies them with great goals, lofty interests, and many daily concerns, they have a great spirit and a good and sublime psyche. One job does not prevent them from another. There is no place for emotional atrophy in them, and there is no place for emotional stagnation in their social and family life.
The love of the Prophet Muhammad (pbuh) for his only daughter, Fatima, was one of the most prominent humane emotional manifestations of the personality of the Noble Prophet. For this reason, he didn’t travel without saying goodbye to his daughter, just as he did not visit Medina without visiting his daughter before anyone. He respected her infront of his wives, with a proper respect that she deserves and said to his followers: “Fatima is a part of me, so whoever upsets her upsets me”. 
Seeing Fatima used to remind the prophet of the most pure, loyal, sympathetic, and gentle woman in the world, (Khadija), who bore great troubles for the sake of her holy husband's goals, and spent all her wealth for the sake of those goals with sincerity and desire.
Fatima Al Zahraa (a.s) used to accompany the bed of her father, the Prophet (pbuh) throughout the days of his illness. He did not leave him for a single moment. The Prophet (pbuh) started talking to her in a small voice, and whoever was there did not know what he had said to his pure daughter in that conversation.
Rather, they witnessed Al Zahraa weeping intensely when her father finished his speech and her tears flowed profusely, but they witnessed that the Prophet referred to her again and spoke to her with something, so she became happy, her face features were cheerful, and smiled optimistically.
These two simultaneous contradictory situations aroused the audience and led them to wonder and astonishment. So, when they asked her about the secret of that sadness and this joy, and they asked her to mention to them the reason for these two contradictory situations, she said: “I would not reveal his secret.”
Then after the Messenger of God (pbuh) died, Al Zahraa (a.s) revealed the truth after Aisha’s insistence and said: “The Messenger of God (pbuh) told me that his death is close and that he will pass over through this pain, so I wept, then he told me that I am the first of his household to follow him, so I laughed”. 
The Biography of the Master of Messengers (pbuh), Ayatollah Al Sheikh Jaafar Subhani
 Sahih Al Bukhari, part 5, page 21
 Al Tabaqat Al Kubra: part 2, page 247, Al Kamil, part 2, page 219