2 Wont to rob churches of their ornaments

Wont > Accustomed

3 And poor men's boxes of their due relief,

boxes > [poor-boxes in church, for alms] relief > {Alms, funds administered from parish doles}

4 Which given was to them for good intents;

intents > purposes

5 The holy saints of their rich vestments 6 He did disrobe, when all men careless slept,

careless > unconscious, free from cares; negligently

7 And spoiled the priests of their habiliments,

spoiled > stripped, robbed habiliments > vestments, attire