IS IT POSSIBLE FOR GOD TO LIE?

Matthew 19:26  But Jesus beheld them, and said unto them, With men this is impossible; but with God all things are possible. (KJV) Hebrews 6:18  That by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us: (KJV)

The Hebrews passage is simply saying that God keeps His promises.  It's essentially saying, 'did God lie to us?  No, that's impossible'.  Not a contradiction. See the related question: Does God Lie? at King17