Prologue to the Rule (paragraph 8)

If, however, you find in it anything which seems rather strict, but which is demanded reasonably for the correction of vice or the preservation of love, do not let that frighten you into fleeing from the way of salvation; it is a way which is bound to seem narrow to start with. (From para. 8 of Prologue to the Rule of Saint Benedict's Rule, trans. by Patrick Barry, OSB, 1997.)

For me, this teaching can apply precisely to the discipline of meditation: Fidelity to the mantra corrects the mind that wanders, the heart that sulks. "It is a way which is bound to seem narrow to start with", as my consciousness finds it way to the Lord.