How "quranic" is the death penalty for apostasy?

Many Imams are preaching the death penalty for apostates who abandon Islam after having been Muslims. Is this penalty authorised by Allah in the Quran? And if not, how can we answer such false preaching?


Sadly there are many blood thirsty Imams today who indeed call for this penalty, but they lie against God. God gives us in the Quran all the proofs to expose those who preach what is contrary to the law of God in the Quran.

Those who believed, then disbelieved, then believed, then disbelieved, then increased in disbelief, God is not to forgive them, nor will He guide them to a path.

In 4:137, God speaks of those who
believed, then disbelieved, then believed, then disbelieved.
The question here is: if a Muslim is put to death as soon as he abandons the faith, then how would it be possible for him to believe again, and then disbelieve again? Surely he would be dead before this sequence happens!

As a result, to apply the death penalty on anyone who reverts would render God's words in 4:137 impossible to happen, and thus invalid!
Rather, God's words in 4:137 prove that there is no penalty of death, nor any other penalty, for those who choose to disbelieve.
Further confirmation is given in 18:29 where God gives all humans the free choice to believe or disbelieve without being penalized or killed:

Say, "The truth is from your Lord", so whoever wills shall believe and whoever wills shall disbelieve. 18:29

Needless to say, there are no penalties of any kind mentioned in the Quran for apostasy. The penalty of such act lies with God alone.