Answers:
God rejected Saul for both disobediences: (1) offering a burnt offering against God’s commandment, and (2) not completely destroying the Amalekites.
Step-by-step explanation:
In I Samuel, you can find that God rejected Saul from being king because he offered a burnt offering against God’s commandment. However, later we read that God rejected Saul from being king for not completely destroying the Amalekites.