Albert Barnes Commentary Exodus 21:19

"if he rise again, and walk abroad upon his staff, then shall he that smote him be quit: only he shall pay for the loss of his time, and shall cause him to be thoroughly healed." — Exodus 21:19 (ASV)

Quit – that is, if one man injured another in a quarrel, forcing him to stay in bed, the aggressor was free from liability for a criminal charge (such as might be based on Exodus 21:12): but he was required to compensate the injured man for the loss of his time and for the cost of his healing.