In all that pertains to mitzvot, the fear of God, and good deeds, one must not content himself with little, as though saying, “What further obligation is there for me?”
In such matters, not only is it a great sin to content oneself with little, it is contemptible.
In the service of God, there is no such notion as “sufficient” and no such grade as “passing.”
In all that pertains to serving God, one must always go further still and aspire to much more.
It has been promised in the Torah, in the Prophets, in the Writings, in the Mishna, and in the Gemara that whenever someone tries to ascend, the way is opened for him.
One need only decide and make an attempt.
No one is forced to advance through those open doors, but one must never rest on his laurels, content with what he has already achieved.
Only in material matters is being content with little a virtue.
In spiritual matters, there is no end to what a person should desire.
–Rabbi Adin Steinsaltz