ما زاغَ البَصَرُ وَما طَغىٰ
The gaze did not swerve, nor did it overstep the bounds.
EXEGESIS
Zāgha (swerve) comes from zaygh, meaning to go astray from the way of balance and uprightness.
Ṭaghā (overstep the bounds) comes from ṭughyān, meaning to overstep the bounds, or to seek superiority over others through sinister and oppressive means.
Baṣar (gaze) is used for the organ that is capable of perception. This perception can be the sight of the eyes, or it can be the insight of the heart.
The zaygh of the gaze is to see something as being different to what it actually is, and the ṭughyān of the gaze is to see something that does not exist at all. Here it means that the Prophet was not mistaken in what he saw, nor did he mistakenly think he saw something which was not there. In this sense this verse is a restatement of verse 2, Your companion has neither gone astray, nor gone amiss, with the difference that verse 2 is about his mission, and this verse is about his vision.
EXPOSITION
The gaze spoken of here is the gaze of the Prophet and it refers to him seeing with the heart, since this verse is a description of the second time he saw Gabriel (Certainly he saw him yet another time (verse 13)) and we were told the first time the seeing took place with the heart (The heart did not deny what it saw (verse 11)). This seeing should also include seeing the Lote Tree spoken of earlier, that which covered it, the garden of the Abode, and anything else witnessed by the Prophet during the Night of Ascension. This is what is understood from the statement of the next verse, Certainly he saw some of the greatest signs of his Lord, which uses the plural (signs).
[1] Tibyan, 9/426; Mizan, 19/32.
[2] Mizan, 19/32.
[3] Tibyan, 9/426.
[4] Raghib, p. 127.
[5] Razi, 28/246; Mizan, 19/32.
[6] Tabrisi, 9/266.