Remain

The Earth and sky have been around since before even man (Genesis 1:1). Generations do come and go, but with respect to them, the Earth does indeed remain “forever”. This is a poetic and metaphorical expression, not to be taken absolutely literally. Matthew 5:18 simply emphasizes how binding God’s law and commands are in that they are even more standing than the sky and Earth, and the same is true of Matthew 24:35, and Revelation 21:1 talks about the new after God’s final victory over evil through the Second Coming of Christ.