Matthew Henry wisely remarks (referring to Saul's blame-shifting in 1 Sam 15:15, 21):
"Those that are willing to justify themselves are commonly very forward to condemn others, and to lay the blame upon any rather than take it to themselves. Sin is a brat that nobody cares to have laid at his doors. It is the sorry subterfuge of an impenitent heart, that will not confess its guilt, to lay the blame on those that are tempters, or partners, or only followers in it."