There came a man of God to Eli, and said to him, Thus says Yahweh, Did I reveal myself to the house of your father, when they were in Egypt [in bondage] to Pharaoh's house?
"I promised  ... but now, Far be it from me"  (1 Samuel 2:30).  All of God's promises are conditional absolutely upon the fidelity of the one to whom the promise came.  Jeremiah spelled this out dramatically in  Jeremiah 18:7-10.