Thank you George Herbert 1633
A man that looks on glass
On it may stay his eye
Or if he pleaseth, through it pass
And then the heav'n espy.
Here the thought is that a man can look at a window pane and chose to arrest his eyes on the glass itself. But he may choose to look through the glass and see what is on the other side. This is how it is with everything we do. We can chose to simply focus on the task or we can look through the task and see (espy) it as an opportunity to serve God. I believe it was CS Lewis who commented that the cynic who 'sees through everything' actually ends up seeing nothing!
All may of thee partake:
Nothing can be so mean,
Which with this tincture (for thy sake)
Will not grow bright and clean.
All, that is all our actions, may benefit from this principle-nothing is so mean (insignificant) that it cannot serve God. The tincture ('a colour that pervades or distinguishes') is the principle of doing all things for his sake, so when added to every action it makes them all 'clean'.