Jamieson, Fausset and Brown on Habakkuk 2:3

3. for--assigning the cause why it ought to be committed to writing: because its fulfilment belongs to the future.

the vision is yet for an appointed time--(Da 10:14; 11:27, 35). Though the time appointed by God for the fulfilment be yet future, it should be enough for your faith that God hath spoken it (La 3:26).

at the end it shall speak--Maurer translates, "it pants for the end." But the antithesis between, "it shall speak," and "not be silent," makes English Version the better rendering. So the Hebrew is translated in Pr 12:17. Literally, "breathe out words," "break forth as a blast."

though it tarry, wait for it--(Ge 49:18).