1. Pada Sutta
Just as all the foot characteristics of roaming creatures are united in the foot of the elephant, and included in it, so, of all profitable conditions which are rooted in earnestness, earnestness is reckoned the chief. S.v.43.
2. Pada Sutta
The simile is the same as the above; but it illustrates the fact that of all the elements which conduce to wisdom, the controlling faculty of insight is reckoned the chief. S.v.231.