When Scripture speaks of rod and staff (cf. Ps. 23:4), you should take these to signify in the prophetic sense judgment and providence, and in the moral sense psalmody and prayer.
For when we are chastened by the Lord with the rod of correction (cf. 1 Cor. 11:32), this is so that we may learn how to mend our ways.
And when we chasten our assailants with the rod of dauntless psalmody, we become established in prayer.
Since we thus wield the rod and the staff of spiritual action, let us not cease to chasten and be chastened until we are wholly in the hands of providence and escape judgment both now and hereafter.
~St Gregory of Sinai
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