'Loins' in the Bible

nevertheless thou shalt not build the house; but thy son that shall come forth out of thy loins, he shall build the house for my name.

And the young men that were grown up with him spake unto him, saying, Thus shalt thou say unto the people that spake unto thee, saying, Thy father made our yoke heavy, but make thou it lighter unto us; thus shalt thou say unto them, My little finger is thicker than my father's loins.