Chapter XV.--Continuing the same subject, she gives certain advice how one should behave in the prayer of quiet. She shows that many souls advance so far, but that few go beyond. The matters treated of in this chapter are very necessary and profitable. Chapter XVI.--On the third degree of prayer; she declares things of an elevated nature; what the soul that has come so far can do, and the effect of such great graces of God. This is calculated to greatly animate the spirit to the praise of God, and contains advice for those who have reached this point. Chapter XVII.--Continues to declare matters concerning the third degree of prayer and completes the explanation of its effects. She also treats of the impediment caused by the imagination and the memory. Chapter XVIII.--She treats of the fourth degree of prayer, and begins to explain [3] in what high dignity God holds a soul that has attained this state; this should animate those who are given to prayer, to make an effort to reach so high a state since it can be obtained in this world, though not by merit but only through the goodness of God. [4] Chapter XIX.--She continues the same subject, and begins to explain the effects on the soul of this degree of prayer. She earnestly exhorts not to turn back nor to give up prayer even if, after having received this favour, one should fall. She shows the damage that would result (from the neglect of this advice). This is most noteworthy and consoling for the weak and for sinners. Chapter XX.--She speaks of the difference between Union and Trance, and explains what a Trance is; she also says something about the good a soul derives from being, through God's goodness, led so far. She speaks of the effects of Union. [5] Chapter XXI.--She continues and concludes this last degree of prayer, and says what a soul having reached it feels when obliged to turn back and live in the world, and speaks of the light God gives concerning the deceits (of the world). This is good doctrine. Chapter XXII.--In which she shows that the safest way for contemplatives is not to lift up the spirit to high things but to wait for God to lift it up. How the Sacred Humanity of Christ is the medium for the most exalted contemplation. She mentions an error under which she laboured for some time. This chapter is most profitable. Chapter XXIII.--She returns to the history of her life, how she began to practise greater perfection. This is profitable for those who have to direct souls practising prayer that they may know how to deal with beginners, and she speaks of the profit she derived from such knowledge. Chapter XXIV.--She continues the same subject and tells how her soul improved since she began to practise obedience, and how little she was able to resist God's graces, and how His Majesty continued to give them more and more abundantly.