"the wise will become wiser and add to his wisdom.." meaning- (the ramchal) says - i think i've said everything necessary in the matter of awakening the heart, and the wise will become wiser etc.. here he's concluding, because this is the final chapter of zeal, the chapter before was watchfulness- which comes from the idea of "remove yourself from evil" be watchful of the negative things- regarding zeal- it's how to be fast with the positive things. so here he concludes the last chapter of zeal-before he goes up to the higher level which is cleanliness