'God will try you with a river, the spring of the corporeal nature; whoever drinks of it, is not of me: meaning whoever gulps from it drinking in immoderation, because the people of [corporeal] nature and the worshippers of passions are lowlier and the most incapacitated of God's creatures, possessing not the strength to fight against the Goliath of the evil-commanding soul nor against Goliath the enemy of religion, since they possess neither [spiritual] zeal nor intensity [and whoever tastes it not, he is of me] except for him who scoops up with his hand, that is, except for the one who contents himself from it in the measure that necessity and need require, without covetousness and over-indulging in it.
But they drank of it, that is, they gulped away at it and became engrossed in it, except a few of them: for those who rise above the filth of [physical] nature and sanctify themselves against coming into contact with it and who disengage themselves from its coverings are few in comparison with those others. God, exalted be He, says but few are they [Q. 38:24] and And few indeed of My servants are thankful [Q. 34:13]: and these are the ones who believed with him [Saul] from among the people of certainty (ahl al-yaqīn), those who knew with the certainty of their light that victory comes not with numbers but through divine assistance. Thus they remained steadfast in the face of what they saw with their own eyes because of the power of their certainty and were hence victorious:
Scarcely is there one who when he is resolute in a matter which he seeks and takes steadfastness as his companion who does not then win a victory