Midras 1 Samuel 17:36: Mekhilta DeRabbi Yishmael, Midrash Tanchuma Buber, Esther Rabbah & Bamidbar Rabbah

David was given a hint and he took it, viz. (I Samuel 17:36) "Both the lion and the bear has your servant slain." Why then should I fear (Goliath, I) who have killed these (other) wild beasts? It must be that something is destined to transpire in Israel and that they are destined to be saved by me! Mordechai was given a hint and he took it, viz.

[(Lev. 21:1:) THEN THE LORD SPOKE UNTO MOSES: SAY UNTO THE PRIESTS.] What is written after this passage (in vs. 10)? AND THE PRIEST THAT IS HIGHEST AMONG HIS BROTHERS.²⁸Tanh., Lev. 8:4; Lev. R. 26:9. Why is he called by the name HIGH?²⁹THE PRIEST THAT IS HIGHEST, without the addition, AMONG HIS BROTHERS, would normally be translated, HIGH PRIEST. Because he was highest (literally: greatest) in five areas: In beauty, in strength, in wealth, in wisdom, and in age.³⁰TYoma 1:6; Yoma 18a; see yYoma 1:3 (39a); cf. ‘Eduy. 2:9; Avot. 6:8. In regard to beauty, because he was more handsome than his brothers. In regard to strength, because he was heroic in strength. Come and consider Aaron. When he waved the Levites (as in a wave offering), he waved twenty-two thousand in one day. How did he wave them? Back and forth, up and down. Ergo: He was highest in strength. Also in regard to wealth, because if he had not been wealthy, his brother priests would have made him wealthy. There is a story about Pinhas the Stone Cutter. When they appointed him high priest, his brother priests went out and saw him cutting stone. So they would not permit him to continue, but filled the quarry before him with gold dinars.³¹Lat.: denarii. [And where is it shown] that, if he had nothing, his brother high priests would magnify (rt.: GDL) him? Where it is stated (in an alternate translation of Lev. 21:10): AND THE PRIEST THAT IS HIGHEST (rt.: GDL) BECAUSE OF HIS BROTHERS. And < this rule applies > not to the high priest alone, but to the king as well. And so you find in the case of David, when he went to fight with Goliath the Philistine, Saul said to him (in I Sam. 17:33): YOU CANNOT GO UNTO < THIS > PHILISTINE … David said to him (in vs. 34–36): YOUR SERVANT TENDED HIS [FATHER'S] SHEEP; < AND WHEN A LION OR A BEAR CAME AND CARRIED OFF A LAMB FROM THE FLOCK, > I WOULD GO OUT AFTER IT, SMITE IT, < AND DELIVER IT OUT OF ITS MOUTH >…. < YOUR SERVANT > SMOTE BOTH THE LION AND THE BEAR, < AND THIS UNCIRCUMCISED PHILISTINE SHALL BE AS ONE OF THEM >…. Saul said to him: And who told you that you could slay him? David replied: Hunting³²Gk.: kynegia. has trained me, Papa. (Vs. 37:) THE LORD WHO DELIVERED FROM THE PAW OF THE LION… < WILL DELIVER ME FROM THE HAND OF THIS PHILISTINE >. Immediately (we read in vs. 38): SAUL CLOTHED DAVID WITH HIS MILITARY GARMENTS…. Now it is written (in I Sam. 9:2): HE WAS A HEAD TALLER³³More literally: TALLER FROM HIS SHOULDERS ON UP. THAN ANY OF THE PEOPLE. When he had clothed him in his garments and seen that they were made for him, he immediately cast a jaundiced eye at him. When David saw that he had offended Saul, he said to him (in I Sam. 17:39): I CANNOT {GO FORTH} [GO] IN THESE, FOR I AM NOT USED TO THEM. Here you learn that even though a person may be short, when he is appointed king, he becomes tall. Why? Because as soon as he is anointed with the anointing oil, he becomes superior to his brothers. David said: I rejoiced over the anointing oil with which I was anointed, in that I shall never move away from my glory. It is so stated (in Ps. 16:9): SO MY HEART REJOICES, AND MY GLORY EXALTS; MY FLESH ALSO DWELLS IN SAFETY.

It is written: “And set it in the ears of Joshua” (Exodus 17:14), this is one of four righteous people to whom a portent was given; two sensed it and two did not sense it. A portent was given to Moses, but he did not sense it. A portent was given to Jacob, but he did not sense it. A portent was given to David and Mordekhai, and they sensed it.
Jacob – the Holy One blessed be He said to him: “I will protect you wherever you go” (Genesis 28:15), and he was frightened. A person to whom the Holy One blessed be He made a promise was frightened, as it is written: “He was frightened” (Genesis 32:8)? Rather, he said: Perhaps when I was in the house of Laban the impure, I became sullied with impurity.
Moses – “and set it in the ears of Joshua,” indicating that Joshua will lead Israel into the land. And it is written: “I pleaded with the Lord [… please let me cross over and see the good land on the other side of the Jordan]” (Deuteronomy 3:23-25).
However, David and Mordekhai were given a portent and they sensed it. David said: “Your servant has smitten both the lion and the bear” (I Samuel 17:36). David said: Am I so important that I was able to smite these wild beasts? Rather, he said: Perhaps an event is destined to befall Israel, and they are destined to be rescued by me.
Mordekhai – “Mordekhai would walk before the courtyard of the harem” (Esther 2:11). He said: Is it possible that this righteous one [Esther] will mary an uncircumcised man? Rather, a great event is destined to befall Israel and they are destined to be rescued by her.