This verse from the Letter of Jeremiah 6:58 (which is considered deuterocanonical or apocryphal by many denominations) is part of a larger argument within the letter about the folly of idolatry. The letter is written to the Jewish exiles in Babylon to warn them against being seduced by Babylonian religious practices, particularly the worship of idols.

Here's a breakdown of the verse's meaning in context:

"Whose gold, and silver, and garments wherewith they are clothed...": This refers to the idols being described. They are adorned with valuable materials like gold, silver, and fine clothing.
"...they that are strong will take from them...": The "strong" are likely referring to thieves, conquerors, or even just ordinary people who lack respect for the idols. The implication is that these valuables are not protected by any divine power of the idols.
"...and go away withal:": The "strong" will steal these valuable items and take them away.
"neither shall they be able to help themselves.": This is the crucial point. The idols are powerless to defend themselves or their possessions. They cannot prevent the theft or punish the thieves.

Overall Meaning:

The verse emphasizes the impotency and uselessness of idols. They are mere inanimate objects that can be easily plundered. This lack of power stands in stark contrast to the true God, who is all-powerful and capable of protecting his people. The author of the Letter of Jeremiah uses this imagery to persuade the exiles that worshipping these idols is not only foolish but also dangerous, as it provides no real security or help.

In essence, the verse highlights the vulnerability and powerlessness of idols as a means to dissuade the Jewish exiles from turning to them for help or worship. It argues that idols cannot even protect themselves, so they certainly cannot protect those who worship them.