Because narrow is the gate, and narrow is the way, which leads unto life, and few there be that find it.
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Augustine of Hippo
AD 430
Serm. in Mont., ii, 22: The Lord had warned us above to have a heart single and pure with which to seek God; but as this belongs to but few, He begins to speak of finding out wisdom. For the searching out and contemplation whereof there has been formed through all the foregoing such an eye as may discern the narrow way and strait gate; whence He adds, “Enter ye in at the strait gate.”