Ravi Yehuda said that Rav said that one should always engage in Torah and mitzvot – even for ulterior motives – since one will eventually do them for the sake of Heaven.

– Sanhedrin 105B

Habit reigns supreme in any sphere and becomes second nature. So if one accustoms himself to despise evil, it will, to some extent, become despicable in truth; likewise, if one accustoms himself to gladden his heart in G-d through reflection upon His greatness, his self impulsion will bring on inspiration from On High. If he pursues this path, perhaps a spirit from above will descend upon him and imbue him with the soul of a Tzaddik.

– Tanya, Chapter 14

With the snap of a whip

the lion roars,

and crouches low

(just for show).

With the snap of a whip

the tamer scores,

and steps on paws

(just for applause).

The lion and the tamer

face to face –

mouths open wide

for the coup-de-grace.

With the snap of a whip

to sting the hide,

who’d have thought

lion and tamer

work side by side?