Hadith: The Messenger of Allah (may Allah's peace and blessings be upon him) used to pray while carrying Umāmah the daughter of Zaynab, daughter of the Messenger of Allah (may Allah's peace and blessings be upon him)

عن أبي قَتَادَةَ الأَنْصَارِيِّ رضي الله عنه قال: «أن رسول الله صلى الله عليه وسلم كان يُصَلِّي وهو حامل أُمَامَةَ بنت زينب بنت رسول الله صلى الله عليه وسلم ». ولأبي العاص بن الربيع بن عبد شَمْسٍ رضي الله عنه : «فإذا سجد وضعها، وإذا قام حملها».
[صحيح] - [متفق عليه]

Abu Qatādah al-Ansāri (may Allah be pleased with him) reported: The Messenger of Allah (may Allah's peace and blessings be upon him) used to pray while carrying Umāmah the daughter of Zaynab, daughter of the Messenger of Allah (may Allah's peace and blessings be upon him). Another narration reported by Abu al-‘Ās ibn Ar-Rabī‘ ibn ‘Abd Shams (may Allah be pleased with him) reads: “When he prostrated himself, he would put her on the ground, and when he stood up, he would carry her.”
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

The Hadīth informs that the Prophet (may Allah's peace and blessings be upon him) would occasionally carry Umāmah, the daughter of his daughter Zaynab, while he was in prayer. He would put her on his shoulder when he was standing and place her on the ground when he bowed or prostrated himself. He did this out of love and affection.