Isaiah 48:7

5 I have even from the beginning declared it to thee; before it came to pass I shewed it thee: lest thou shouldest say, Mine idol hath done them, and my graven image, and my molten image, hath commanded them.

6 Thou hast heard, see all this; and will not ye declare it? I have shewed thee new things from this time, even hidden things, and thou didst not know them.

They are created now, and not from the beginning; even before the day when thou heardest them not; lest thou shouldest say, Behold, I knew them.

8 Yea, thou heardest not; yea, thou knewest not; yea, from that time that thine ear was not opened: for I knew that thou wouldest deal very treacherously, and wast called a transgressor from the womb.

9 For my name’s sake will I defer mine anger, and for my praise will I refrain for thee, that I cut thee not off.

This was said to Israel at a particular time, so it is wise to read it together with the surrounding text. Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
They are created now, and not long ago; you have not heard of them before today. So you cannot claim, ‘I already knew them!’
KJV
They are created now, and not from the beginning; even before the day when thou heardest them not; lest thou shouldest say, Behold, I knew them.
WEB
They are created now, and not from of old. Before today, you didn’t hear them, lest you should say, ‘Behold, I knew them.’
ASV
They are created now, and not from of old; and before this day thou heardest them not; lest thou shouldest say, Behold, I knew them.
DARBY
they are created now, and not long ago; and before this day thou hast not heard them, lest thou shouldest say, Behold, I knew them.
BLB
Now they have been created, and not from then; and before this day, and you did not hear of them, lest you should say, ‘Behold, I knew them.’
ÅB
Nå først er det skapt, og ikke for lenge siden, og før idag hadde du ikke hørt det, for at du ikke skulle si: Det visste jeg!
OTB
De er skapt nå, og ikke for lenge siden; du har ikke hørt om dem før i dag, så du ikke kan si, 'Ja, jeg visste dem.'
B1930
Nu først er det skapt, og ikke for lenge siden, og før idag hadde du ikke hørt det, forat du ikke skulde si: Det visste jeg!

Study notes (Tyndale)

Original text and word study