Midrash sa Josue 24:21: Sifrei Devarim

And thus do you find with Joshua, that he rebuked Israel only close to his death, as it is written (Joshua 24:15) (Joshua said) "If it is evil in your eyes to serve the L-rd, choose this day whom you will serve — the gods that your forefathers served or the gods of the Emorites in whose land you dwell — and I and my house will serve the L-rd." And thus do you find with Samuel, that he rebuked Israel only close to his death, as it is written (I Samuel 12:3) "Here I am (before my death); testify before me in the presence of the L-rd and in the presence of His anointed … (4) and they said: You have not robbed us, etc. (5) and he said: The L-rd is witness unto you this day. And they said: Witness!"