Jamieson, Fausset & Brown

looking--having fixed his eyes, with significant gaze, on Jesus. as he walked--but not now to him. To have done this once (see on Joh 1:29) was humility enough [BENGEL]. Behold, &c.--The repetition of that wonderful proclamation, in identical terms and without another word, could only have been meant as a gentle hint to go after Him--as they did.