Fear not. ashamed. Reference to Pentateuch (Leviticus 26:6). Compare Isaiah 44:16; Isaiah 44:17.
the shame of thy youth. Reference to Israel's days of idolatry. Compare Jeremiah 3:24; Jeremiah 3:25.
Related Commentaries of Isaiah 54:4
Isaiah 54:4
4 Fear not; for thou shalt not be ashamed: neither be thou confounded; for thou shalt not be put to shame: for thou shalt forget the shame of thy youth, and shalt not remember the reproach of thy widowhood any more.