YOU SAID:

If you don't walk today, you must run tomorrow.

INTO JAPANESE

今日歩かないのなら、明日走らなければなりません。

BACK INTO ENGLISH

If you don't walk today, you have to run tomorrow.

INTO JAPANESE

今日歩いていないなら、明日走らなければなりません。

BACK INTO ENGLISH

If you're not walking today, you'll have to run tomorrow.

INTO JAPANESE

今日歩いていないのなら、明日走らなければなりません。

BACK INTO ENGLISH

If you're not walking today, you'll have to run tomorrow.