For a small moment - The Chaldee and Syriac render this, 'In a little anger.' Lowth has adopted this, but without sufficient authority. The Hebrew means, 'For a little moment;' a very short time. The reference here is probably to the captivity at Babylon, when they were apparently forsaken by Yahweh. Though to them this appeared long, yet compared with their subsequent prosperity, it was but an instant of time. Though this had probably a primary reference to the captivity then, yet there can be no impropriety in applying it to other similar cases. It contains an important principle; that is, that though God appears to forsake his people, yet it will be comparatively but for a moment. He will remember his covenant, and however long their trials may seem to be, yet compared with the subsequent mercies and the favors which shall result from them, they will seem to be but as the sorrows of the briefest point of duration (compare 2 Corinthians 4:17).

But with great mercies - The contrast here is not that of duration but of magnitude. The forsaking was 'little,' the mercies would be 'great.' It would be mercy that they would be recalled at all after all their faults and crimes; and the mercy which would be bestowed in the enlargement of their numbers would be inexpressibly great.

Will I gather thee - Will I collect thee from thy dispersions, and gather thee to myself as my own people.

Isaiah 54:7 Parallel Commentaries

Early Battles
Six months of joyous service amongst the Welsh miners was cut short by a telegram announcing to the sisters the serious illness of Mrs. Lee. Taking the news to their Divisional Commander, they were instructed to Headquarters. It was found that the illness was due to shock. The income from investments of the little estate left by Mr. Lee had dwindled; it now had disappeared altogether. Captain Lucy faced the matter with her usual practical decision. 'Mother, darling, there are two ways out. Either …
Minnie L. Carpenter—The Angel Adjutant of "Twice Born Men"

The Ascension of Messiah to Glory
Lift up your head, O ye gates; and be ye lift up, ye everlasting doors; and the King of glory shall come in. Who is this King of glory? The LORD strong and mighty, the LORD mighty in battle. Lift up your heads, O ye gates; even lift them up, ye everlasting doors; and the King of glory shall come in. Who is this King of glory? The LORD of hosts, he is the King of glory. T he institutions of the Levitical law were a "shadow" or "sketch" of good things to come. They exhibited a faint and general outline …
John Newton—Messiah Vol. 2

The Great Crisis in Popular Feeling - the Last Discourses in the Synagogue of Capernaum - Christ the Bread of Life - Will Ye Also Go
THE narrative now returns to those who, on the previous evening, had, after the miraculous meal, been sent away' to their homes. We remember, that this had been after an abortive attempt on their part to take Jesus by force and make Him their Messiah-King. We can understand that the effectual resistance of Jesus to their purpose not only weakened, but in great measure neutralised, the effect of the miracle which they had witnessed. In fact, we look upon this check as the first turning of the tide …
Alfred Edersheim—The Life and Times of Jesus the Messiah