(I an adding this answer here, which was already posted elsewhere, at the request of the OP.)
R. Elishevitz (a very great Talmid Chacham from Russia who later moved to Israel about 80 years ago) in his sefer אלף המגן explains how the Haftorah for parshas Tazria completely corresponds to the Torah reading:
The Haftorah for parshas Tazria - Kings Ⅱ 4:42-5:19 - talks about how Na’aman, who was supra-naturally afflicted with a skin blemish, went to Elisha the prophet and was cured, and this corresponds to parshas Tazria which discusses similar afflictions of the body and clothing.
But the Haftorah starts three verses earlier with the story of how a gift of food was sent to to Elisha and how he was miraculously able to feed his many students from this small amount of food. What relevance does this have to the parsha?
It would not have been so remarkable if these three verses were at the beginning of the section which talks about Na’aman, but when we look in the Tanach we see that these three verses are in a separate paragraph, so why was there any need to include them in the Haftorah?
A similar question can be asked on the parsha itself which starts with the laws of a woman who gives birth. What relevance does this have to the main subject of the parsha?
We can answer these questions with a parable about a soldier who returned home during his month’s furlough from the army, and who went around town boasting about the certificate that he carried with him testifying to his bravery, because once several of the enemy attacked and tried to take away his company’s standard (guidon/pennant), and had they succeeded it would have been a great source of shame to the company. But he managed to fight them all off and defend the standard, and hence his certificate of bravery.
After a few days another soldier arrived on furlough, and he too boasted about the certificate that he carried with him testifying to his bravery, because he once went over to where the enemy were and successfully stole their standard after attacking several of the enemy, causing them great shame. Clearly the feat of the first soldier paled into insignificance compared to the feat of the second soldier!
These two soldiers are the parsha and the Haftorah. The job of the woman is to raise her children to serve Hashem so that the afflictions mentioned in the rest of the parsha never come upon them. This is like the first soldier, who was able to defend but not attack.
But the beginning of the Haftorah shows the greatness of the prophet who taught Torah to Yisrael and who taught and sustained many students. Not only is one such as him able to defend against afflictions, but he is even able to cure them as the rest of the Haftorah relates. This is like the second soldier.
Thus there is a clear correspondence between the Torah and the Haftorah in their entirety, and the relevance of the first verses is now clear.