I'm pretty sure it's a Bible quote & it has a much broader application than just creating. Chaining yourself to an ideal has a very similar effect & is perhaps more limiting than comparing your idea to what already exists.

I feel like the creation process largely requires you to get out of your own way. To allow the inspiration to flow to & through you rather than force it out with sheer will.

The doubt over your own abilities & how the creation might be received doesn't help.

An ideal outcome is subjective & only reached by comparison with what you known & have experienced. 

One of the beautiful aspects of creating is enjoying the unexpected outcomes from the process. The more you let go of expectations, the easier the creation process becomes. 

Achieving an ideal outcome is near impossible but iteration of both the solution & your approach is important. Create then iterate. Judgement & comparison to your ideal before & during the creation process just gets in the way.