Abraham could have avoided the whole child abuse and attempted murder of his “only” son, Isaac, if he had paid a little more attention to god’s command. You see, multiple bible verses show that Abraham had more than one son. He had Isaac. And Ishmael (who was born before Isaac). And Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah. Abraham should have done nothing, since god’s request to kill Isaac was completely impossible. It is not possible to murder your only son when you have more than one.
The only way that believers can defend this contradiction is if they say that god does not recognize illegitimate children (as shown here). That’s messed up, god.