Contradiction with Matthew 19:26
Jesus states that "with God all things are possible," which supports, rather than contradicts, the power of God described in Ephesians 3:20.
Matthew 19:26: But Jesus beheld [them], and said unto them, With men this is impossible; but with God all things are possible.
Contradiction with Jeremiah 32:27
God declares nothing is too hard for Him, echoing Ephesians 3:20's emphasis on God's power, so it isn't a contradiction.
Jeremiah 32:27: Behold, I [am] the LORD, the God of all flesh: is there any thing too hard for me?
Contradiction with Genesis 18:14
Questions if anything is too hard for the Lord, reinforcing Ephesians 3:20's theme of divine ability.
Genesis 18:14: Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah shall have a son.