The Song of David is read as the haftarah twice during the year. Once with parshat Haazinu (when it falls between Yom Kippurand Sukkot), because it is similar to Moses's song of Haazinu, and again on the seventh day of Passover, when we read Az Yashir, the song we sang at the splitting of the Sea of Reeds.

When we read Az Yashir during the year, the haftarah is from the Song of Deborah, because at the splitting of the sea, the women were more joyous than the men. While the men sang, the women sang with dances and tambourines. Therefore, we sing the song of a woman, the Song of Deborah.

Why then do we read the Song of David on the seventh day of Passover? It is explained that on the seventh day of Passover, the light of Moshiach shines bright, as the day has redemptive qualities to it. That is why it was on this day that the Jewish people went through the Sea of Reeds, finally becoming free from the Egyptians. Since King David is the father of Moshiach, we read his song.

The Song of David is recorded twice in the Bible, once in the book of Samuel, and again, with variations, in Psalms. For the haftarah, the one from Samuel is read.

King David sang this song in gratitude to G‑d, who saved him from his enemies and from King Saul. It is written in the Bible twice, since there are many lessons to be learned from it with regards to our personal salvation from dark and difficult situations and challenges. I will just mention a few.

The haftarah tells us that G‑d, “surrounded Himself with a canopy of darkness, from clouds of water, bound together…” This is said, not in a negative way, but rather, in a positive way. What is positive about G‑d being in the darkness?

First, it is darkness that defines light. Second, darkness and difficulties bring out light in two ways. When a person is faced with a challenge, it brings out the will in him or her to overcome and break through the darkness. By overcoming the darkness, the light is greater than it would have been without the difficulty.

However, there is much more that can be achieved with this darkness. Sometimes, the darkness is so great that it feels insurmountable. When this happens, the only strategy is to turn the darkness into light. This is accomplished by taking the difficulty and finding a way to use it for good. It makes you realize that the darkness was not darkness at all. In Chassidic parlance this is “the great light which comes out of the darkness.”

This message is found later in the haftarah as well. King David says, “You are my lamp, G‑d, and G‑d lights my darkness.” A lamp dispels darkness, yet the darkness still exists; it is just overcome by light. “G‑d lights my darkness” is when the revelation of G‑d is so great that the darkness ceases to exist.

How did King David achieve these great salvations? He says that G‑d “makes my legs straight like a doe’s.” Rashi explains that a female deer’s legs are straighter than the male’s. What does a doe’s legs have to do with our haftarah?

A deer prances freely and can go far on its legs. This symbolizes that we are capable of doing a lot. Straight legs symbolize acceptance of G‑d's will without question, just as legs do the bidding of the head, taking it from place to place, without question. He speaks of a female deer, because women, being closer to G‑d, are more likely to do what He wants without question. (We see this regarding the sin of the Golden Calf, when the women refused to join in the sin.) King David is saying that because he had unquestioning faith, which women naturally have, he merited these great salvations. As the verse continues, “He stands me on high places.” This means, that when we act this way, G‑d doesn't just save us. He puts us above any possibility of strife, challenges, darkness, difficulties, pain, suffering, etc.

May we merit this already, as we have all done G‑d's bidding and suffered for it. It is time for Moshiach to come. May he come soon.