In Jeremiah 6:10 Jeremiah responds to the Lord with a question. It therefore makes sense that the Lord is referring to Jeremiah in Jeremiah 6:9 as the grape-gatherer who must pass your hand again over its branches.
It is the enemy that will bring destruction on Judah, but Jeremiah is the prophet who must move through the people with his message of this coming judgment.1 Jeremiah’s role in the analogy is that of the vineyard owner, examining every branch of the vine to see whether the fruit was ripe for cutting.2 The way he examines the vine is through the preaching of his message of coming judgment.
9 Ainsi parle l'Eternel des armées: On grappillera comme une vigne les restes d'Israël. Portes-y de nouveau la main, Comme le vendangeur sur les ceps.