goodly > fine, beautiful heap > pile; hence: large building
2 And spoke the praises of the workman's wit;
wit > skill
3 But full great pity, that so fair a mould
full > very, exceedingly mould > form, structure
4 Did on so weak foundation ever sit:
so > such [a]
5 For on a sandy hill, that still did flit
still > continually flit > yield, crumble (see Matt. 7.26-7)
6 And fall away, it mounted was full high,