Jesus constrained them; that is, he commanded them to go away before him. No doubt but they were very loth to leave him, and to go without him; both out of the love which they have to him and themselves.
Such as have once tasted the sweetness of Christ, are hardly drawn away from him: however, as desirous, as the disciples were to stay with Christ, yet at his word of command they depart from him.
Where Christ has a will to command, his diciples and followers must have a will to obey.