33 But Saul hurled his spear at him to kill him. Then Jonathan knew that his father intended to kill David.

Read 1 Samuel 20:33 Using Other Translations

And Saul cast a javelin at him to smite him: whereby Jonathan knew that it was determined of his father to slay David.
But Saul hurled his spear at him to strike him. So Jonathan knew that his father was determined to put David to death.
Then Saul hurled his spear at Jonathan, intending to kill him. So at last Jonathan realized that his father was really determined to kill David.