Souls in good spiritual health

How can we know with certainty when souls are in good spiritual health or not? That is, beyond assuming that we are not in mortal sin? According to Gregory Palamas – the theologian and saint of the Divine Light – “the only proof of a soul in good health” is when it attains theoria – the vision of God, through the acquisition of the Holy Spirit; that is, living in His fullness. This because “the sign of a healthy soul is that it has been purified and has attained to theoria . . . Those who have not received this illumination of divine grace and have not reached . . . the theoria of God are ailing . . . [since] theoria is the fruit of a healthy soul, an outcome and a state that deifies” (Met. Hierotheos. 2010. The science of spiritual medicine, p. 273). It is true that the virtues, that so many emphasize, heal the soul. But when the soul is healed, it beholds God – the vision of the Divine Light (ibid.) – otherwise there would be no point whatsoever in acquiring the virtues.