SB 3.17.16

tāv ādi-daityau sahasā
 vyajyamānātma-pauruṣau
vavṛdhāte ’śma-sāreṇa
 kāyenādri-patī iva
Word for word: 
tau — those two; ādi-daityau — demons in the beginning of creation; sahasā — quickly; vyajyamāna — being manifest; ātma — own; pauruṣau — prowess; vavṛdhāte — grew; aśma-sāreṇa — steel-like; kāyena — with bodily frames; adri-patī — two great mountains; iva — like.
Translation: 
These two demons who appeared in ancient times soon began to exhibit uncommon bodily features; they had steel-like frames which began to grow just like two great mountains.
Purport: 

There are two classes of men in the world: one is called the demon, and the other is called the demigod. The demigods concern themselves with the spiritual upliftment of human society, whereas the demons are concerned with physical and material upliftment. The two demons born of Diti began to make their bodies as strong as iron frames, and they were so tall that they seemed to touch outer space. They were decorated with valuable ornaments, and they thought that this was success in life. Originally it was planned that Jaya and Vijaya, the two doorkeepers of Vaikuṇṭha, were to take birth in this material world, where, by the curse of the sages, they were to play the part of always being angry with the Supreme Personality of Godhead. As demoniac persons, they became so angry that they were not concerned with the Supreme Personality of Godhead, but simply with physical comforts and physical upliftment.