Perhaps Jael was on the lookout, to show mercy to any poor Israelite which might have fled, from the battle. And if so, what must have been her surprise when she found Sisera at her door? Her hospitality to this sworn foe of Israel was no doubt intended for the better, and more easy accomplishment of the purpose, which probably by this time, when she saw his reduced strength and fatigue, she had conceived in her mind to perform.
Related Commentaries of Judges 4:18
Judges 4:18-20
18 And Jael went out to meet Sisera, and said unto him, Turn in, my lord, turn in to me; fear not. And when he had turned in unto her into the tent, she covered him with a mantle.c
19 And he said unto her, Give me, I pray thee, a little water to drink; for I am thirsty. And she opened a bottle of milk, and gave him drink, and covered him.
20 Again he said unto her, Stand in the door of the tent, and it shall be, when any man doth come and enquire of thee, and say, Is there any man here? that thou shalt say, No.