This verse has two halves with 5a repeating much of verse 3, while 5b offers another reason for God’s announcements of old, parallel to verse 4 (see the introductory comments there).
I declared them to you from of old, before they came to pass I announced them to you: I declared them to you from of old is similar to the opening line of verse 3. The pronoun them is not in the Hebrew text but it is understood. It refers back to the “former things.” But the difficulty with supplying them is that in the following clause, before they came to pass (literally “before she/it came”), the Hebrew verb is actually singular. New Jerusalem Bible is an exception among major versions in preserving a singular “it” by rendering these two lines as “As I told you about it long before, before it happened I revealed it to you.” But the change from the plural “former things” to the singular “it” is not significant since Hebrew often makes such grammatical changes without necessarily implying a change of referent. Translators will probably use plural forms throughout to be consistent. I announced them to you is literally “I caused you to hear [them].” Normally translators will look to verse 3 for the expressions to be used in these two lines. However, Good News Translation refers to the “former things” as “your future.”
Lest you should say, ‘My idol did them, my graven image and my molten image commanded them.’: This half of the verse explains why God announced events before carrying them out. Clearly, much of popular religion in Israel believed that idols were in control of events rather than Yahweh. But God’s announcement long ago that these events would happen was proof that he alone was in control. Thus he preempted the people’s claims that their idols did them or commanded them, that is, caused the events to happen.
The Hebrew conjunction translated lest (New International Version “so that … not”) introduces something that should be avoided. The possibility that the people would claim that their own idols had caused things to happen is what God intended to avoid. There are two clauses identifying the possible claims the people might make, with three terms for idols—idol, graven image, and molten image. As noted before, Isaiah often uses three expressions to emphasize a point. Here the implication is that within Israel the popular use of religious images was widespread. The Hebrew word rendered idol occurs only here in the Old Testament, so its precise meaning is uncertain. Its meaning is decided on the basis of the parallel terms graven image and molten image. One commentator notes that there is a word in Hebrew meaning “pain” (used in 14.3) that sounds like the term for idol, so there may be a wordplay here also. A graven image is a carved image, usually of wood (see the comments on 10.10), and a molten image is one cast in metal (see the comments on 41.29 and 42.17). The words for idol, graven image, and molten image are singular in Hebrew, but they may be rendered as plurals since they have a collective sense here (so Good News Translation, Contemporary English Version).
The direct speech concerning the idols may be expressed as indirect speech if necessary, as in Good News Translation (see also the second example below).
Translation examples for this verse are:
• I announced them to you long ago,
before they happened I told you of them,
so that you could not say,
‘My idol did them,
my carved image and my molten image ordered them.’
• I announced these things to you long ago,
even before they happened I warned you of them;
otherwise you might claim that your idols had done them,
and that your carved and molten images had ordered them.
Quoted with permission from Ogden, Graham S. and Sterk, Jan. A Handbook on Isaiah. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here .