Deuteronomy 32:34

Is not this laid up in store with me, and sealed up among my treasures?

The verse stands in Moses' song recounting God's dealings with Israel. That song was framed from the waymarks God set up in His dealings with ancient Israel to be taught by parents to children, with its memorials gathered up, laid up in sight, and carefully preserved, so that when children asked the whole story of His providential dealings, marked goodness, mercy, care, and deliverance could be repeated and kept in mind with praise and thanksgiving for His goodness and wonderful works. It also looks ahead prophetically to future events, including the final victory of the faithful when Christ comes again in power and glory.

It means that God keeps appointed judgment, recompense, and the evil and corruption due for rebellion in store with Him, sealed among His treasures until the time He has set. What is thus laid up includes Israel becoming a perverse and crooked generation, provoking God to jealousy with strange gods and sacrificing to devils, and becoming as the vine of Sodom with grapes of gall and wine as the poison of dragons and the cruel venom of asps. This storing means that God numbers steps, watches over sin, and holds the record of transgression and iniquity sealed as in a bag for the day of calamity.

The surrounding lines declare that vengeance and recompense belong to Him, that calamity and foot-sliding judgment upon His enemies will come swiftly in due time and is near at hand, marking the day of judgment at hand, together with mercy toward His land and people. The prophecy reveals God's abhorrence of sin, and its warning about Judah's apostasy made Josiah tremble for the nation's future.