the imitation of Christ, the 3rd book: chapter xxxiii (instability of the heart and of directing the aim towards God)

OF INSTABILITY OF THE HEART AND OF DIRECTING THE AIM TOWARDS GOD “” My Son, trust not your feeling, for that which is now, will be quickly changed into somewhat else. As long as you live, you are subject to change, howsoever unwilling; so that you are found now joyful, now sad; now at peace, [...]