Three traps

....And the Prophet, may God bless him and grant him peace used to say in his prayers, 'I seek refuge in Thee from the evil which may be in my ear, my eye, my heart and my semen' (Abu Daud, Tirmidhi)... It is told that Moses, upon whom be peace,, was once sitting in company when satan came up to him wearing a cloak in which he assumed many colors. When he drew near to him he took this off and set it aside. Then he said, ‘Peace be upon you Moses!’ Moses ask him who he was and he replied, ‘I am satan’. ‘God slay you!’ Moses said. ‘What brings you here?’ And he answered, ‘I have come to greet you in view of your great rank in the sight of God’. ‘What was it that I saw you wearing?’ he asked, and he replied, ‘A cloak with which I snatch away the hearts of the descendants of Adam’. ‘What is it then,’ Moses asked, ‘that a man does which enables you to prevail over them?’ And he replied, ‘He becomes pleased with himself, and considers that he has many good deeds to his credit, and forgets his sins. Now, I would warn you against three things! Never be alone with a woman who is not lawful for you, for never does a man do so without having me, not my companions, as his companion, so that I tempt them both with one another. Never make a vow to God without fulfilling it. And never prepare something to give as charity and then fail to give it, for never does a man do so without having me, not my companions, as his companion, so that I prevent him from giving it [at a later time]’. Then he went away, crying, ‘Woe is me! Moses has learnt something against which to warn the descendants of Adam!’

from The Revival of the Religious Sciences/Ihya Ulum al-Din, Hujjatul Islam/Proof of Islam, Imam Abu Hamid al-Ghazali, may Allah be well pleased with him