"I heard Al-Qasim saying: "Abdullah bin 'Abdullah informed me that he heard 'Abdullah bin 'Umar saying: "From the Sunnah of the prayer is to lay your left foot on the ground, and raise your right foot." (Using translation from Abū Dāʾūd 959)  

أَنْ تُضْجِعَ رِجْلَكَ الْيُسْرَى وَتَنْصِبَ الْيُمْنَى»