Prudentia acquisita causatur ex exercitio actuum, unde indiget ad sui generationem experimento et tempore, ut dicitur in II Ethic. Unde non potest esse in iuvenibus nec secundum habitum nec secundum actum. Sed prudentia gratuita causatur ex infusione divina. Unde in pueris baptizatis nondum habentibus usum rationis est prudentia secundum habitum, sed non secundum actum, sicut et in amentibus.
Acquired prudence is caused by the exercise of acts, wherefore “its acquisition demands experience and time” (Ethic. ii, 1), hence it cannot be in the young, neither in habit nor in act. On the other hand gratuitous prudence is caused by divine infusion. Wherefore, in children who have been baptized but have not come to the use of reason, there is prudence as to habit but not as to act, even as in idiots.
S Th II II 47 14 ad 3