My father and Ali bin Ishaq narrated to us, saying, Abdullah bin Mubarak informed us, Abdul-Rahman bin Yazid bin Jabir narrated to us, Zayd bin Artah narrated to me, from Jubayr bin Nufayr, from Abu Darda, who said, "I heard the Messenger of Allah ﷺ say, 'Seek out your weak ones for me, for you are only granted provision and victory through your weak ones.'"
حدثنا إبراهيم بن إسحاق حدثنا ابن المبارك
أبي وعلي بن إسحاق أنا عبد الله بن المبارك حدثنا عبد الرحمن بن يزيد بن جابر حدثني زيد بن أرطاة عن جبير بن نفير عن أبي الدرداء قال سمعت رسول الله ﷺ يقول أبغوني ضعفاءكم فإنكم إنما ترزقون وتنصرون بضعفائكم
Its isnad is sahih. From his route, and Ibn Ishaq made clear in the first instance that he said "haddathana." Abu Dawud narrated the hadith in 3/33, number 2594, in the chapter on jihad, and Hakim graded it sahih in 2/106, and Dhahabi agreed with him. Bayhaqi also narrated it from him in 3/345.