The Messenger of Allah ﷺ said, "Whoever hears of Dajjal should keep far away from him. By Allah, a man will come to him thinking himself a believer, yet he will end up following him because of the doubts Dajjal stirs up," or "because of what he sends forth of doubts." Thus he said it.
حدثنا موسى بن إسمعيل حدثنا جرير حدثنا حميد بن هلال عن أبي الدهماء قال سمعت
قال رسول الله ﷺ من سمع بالدجال فلينأ عنه فوالله إن الرجل ليأتيه وهو يحسب أنه مؤمن فيتبعه مما يبعث به من الشبهات أو لما يبعث به من الشبهات هكذا قال
[Its isnad is sahih] Ahmad reported it: 4/431, from the hadith of Humayd bin Hilal, through him, and Hakim graded it sahih according to the criterion of Muslim: 4/531.