佛說處處經 1.8

1.8

「佛舉右手，復有四因緣：一者、欲令十方人皆來學道隨行意；二者、為欲示人我所行福，今得是相；三者、勸人皆令持戒；四者、威儀自爾，亦為不欲見人惡態，是故舉一切右手。

"That the Buddha raises his right hand is furthermore due to four nidānas: first, he wishes to cause people of the ten directions to all come, learn the Way, and follow his intention; second, wishing to show people the merit I practiced, having now attained these marks; third, encouraging people to all observe the precepts; fourth, his deportment is naturally so, and also because he does not wish to see people's evil manners; therefore he always raises his right hand.