Rashi: They will be My handiwork, i.e. Tzadikim amidst him. When he sees that his children, My handiwork, sanctify My name, like Chananyah, Misha'el and Azaryah, his face will not whiten.

Radak: When he sees that his children, are truly his children, that they go in the good path, and when he sees My acts amidst him, what I will do to Machaneh Ashur that comes to in his land.

Malbim: My wonders amidst him will be for the honor and glory of his children.

Radak: When he sees that his children will sanctify My name over the great miracle. When they sanctify His name, they will say Kedosh Yakov and Elokei Yisrael. Then Yakov will not be ashamed; he will rejoice. Kedushas Kel is attributed to Yakov, and not to the other Avos. It says also "Hashem Tzevakos Avir Yakov", "Kedosh Yisrael Avir Yakov", "Hashem Tzevakos Elokei Yisrael", "Kedosh Yisrael Moshi'ech", "Go'alchem Kedosh Yisrael" (1:24, 21:10, 43:3, 14). Some of these could refer to Klal Yisrael, but some clearly refer to Yakov Avinu. This is because Yakov saw Kedushas Kel in the vision of the ladder.

Radak (22): They will truly be called Beis Yakov; Yakov will not be ashamed of their deeds. Rather, he will rejoice from his children's deeds in the days of Chizkiyah, when they will return to the good path and sinners will be wiped out in the wars beforehand. Those who remained from them and learned from their deeds, they were not Resha'im like them. Those whose spirits strayed and were evil, they will return to the good path. Yakov would not be ashamed of them if he were alive.

Malbim: Until now, he was ashamed of their bad deeds. Now he will not, for they will sanctify My name via their good deeds.

Radak: In their praise, they will give (attribute) to Him strength, that he struck in Machaneh Ashur 185,000 ¹ in one night. Their strength and multitude did not help them.

Malbim: Via the miracles that He will do amidst them, they will show everyone His unlimited ability and strength.