The one is good already, while it is possible that the other may turn out bad.
A gude cause maks a strong arm.
A gude conscience is the best divinity.
A gude day's darg may be done wi' a dirty spade.
A gude dog ne'er barkit about a bane.
A gude face needs nae band, and an ill ane deserves nane.
A gude fellow is a costly name.
A gude fellow ne'er tint but at an ill fellow's hand.
A gude goose may hae an ill gaiflin.
A gude green turf is a gude gudemother.