‘ And the manna ceased on the morrow after they had eaten of the produce of the land, neither had the children of Israel manna any more, but they ate of the fruit of the land of Canaan that year.'
Manna was ‘wilderness food'. The ceasing of the manna was the final sign that their wanderings were over. From now on they would eat of the good things that the promised land provided. So the crossing of the Jordan, followed by circumcision indicating a new birth for the nation (compare Isaiah 48:1 ‘are come forth out of the waters of Judah' where the ‘breaking of the waters' at birth may well have been in mind), together with the celebration of Passover, the feast of deliverance, now resulted in full provision for the future.
For this compare Exodus 16:35 where it was declared that after forty years the manna would cease when they reached the borders of Canaan.