What did the Apostle of Allah (peace be upon him) ask Jabir b. 'Abdullah to do after paying him back with an addition?
 Jabir b. 'Abdullah reported:                      The Apostle of Allah (may peace be upon him) owed me a debt; he paid me back and made an addition (of this). I entered the mosque and he (the Holy Prophet) said to me: Observe two rak'ahs of prayer.