The Messenger of Allah ﷺ used to fall behind during the march, urging the weak to keep up, letting them ride behind him, and praying for them.
حدثنا الحسن بن شوكر حدثنا إسمعيل ابن علية حدثنا الحجاج بن أبي عثمان عن أبي الزبير أن
كان رسول الله ﷺ يتخلف في المسير فيزجي الضعيف ويردف ويدعو لهم
Sourcing, [sahih] Hakim narrated it, 2/115, from the hadith of Ismail bin Ulaya through this route, and graded it sahih according to the criteria of Muslim, and Dhahabi agreed with him. The hadith has corroborating narrations.