Why Congress will sing only the first two stanzas of Vande Mataram, and what the other four say

The Congress Working Committee (CWC) has decided that only the first two stanzas of Vande Mataram will be sung at party programmes, amid BJP attacks over the National Song's rendition at its Independence Day programme and later at an event in Goa. The Congress’s highest decision-making body cited a 1937 CWC resolution to back its stand, arguing that the leading lights of the freedom movement, including Mahatma Gandhi and Rabindranath Tagore, had backed limiting the public rendition of Vande Mataram to its first two stanzas. The row comes months after Parliament made intentional attempts to prevent or disrupt the singing or playing of Vande Mataram an offence. Why did the Congress in 1937 distinguish between the first two stanzas and the rest of the song? What do the remaining four stanzas say, and why have they been contentious?