Guru Nanak defines a complete person as the one who is fully absorbed in oneness (Raag Sri).
Guru Amardas implies it's not enough to just be absorbed. It's important to show this path to others. The complete Guru is one who is fully absorbed and shares the path of oneness through his words:
Guru Arjan Dev implies in the following Shabad that it is possible to become "complete" yourself by being in the company of the "complete". If oneness resides in your heart, you are complete and everything becomes complete:
The following is an interesting take (and mostly synchronous with the teachings of Guru Nanak) on what a true Guru is ...
Are you tired of hearing about yoga teachers behaving in “less than yogic” ways?
The problem is as old as power itself, and is lived out in almost any religious, spiritual or political context you can imagine.
If you're looking for a guru or a spiritual teacher, you may want to have this checklist in hand before you commit your spiritual life to one:
1. True gurus don't expect anything in return.
They might take payment for their classes, they might take donations for their cause, but they will give you their best, regardless. Beware of teachers who demand great sacrifices (economic or otherwise) to be in their presence.
2. True gurus are not attached.
They are not attached to your getting any results, to you following them, or to you liking them. Therefore, they won't be angry or disappointed with you, regardless of your actions. Beware of controlling, demanding, forceful or manipulating impostors.
3. True gurus help you find your own way.
They may have a specific path to recommend, but fully acknowledge that there are many routes to enlightenment, and you should follow or even create the one that most suits you. Remember: the truth is ONE, the paths are many.
4. True gurus empower your own inner guru.
They will always help you see, understand and tap into your own power, grace, and beauty. When you've been with a true guru, your own light will shine brighter, and you'll believe more in yourself.
5. True gurus want your freedom and independence.
If they're the real deal, they will urge you to create a life that works well when they're not around. If they're a charlatan, they will want to make you feel lost and needy when not in their presence.
6. True gurus don't need to be affirmed by others.
They don’t need an entourage, nor a following. So forget about phonies who demand your dedication, offerings and allegiance to them and their cause, or who are constantly in need of new devotees. Remember, it’s not about them; it’s about you!
7. True gurus walk their talk.
It is easy to teach divine living, but very hard and rare to live divinely. Thus the true guru will teach by example, and will be non-materialistic, fair, grounded, peaceful, strong, generous, humble, and whatever else we would consider universally good.
8. True gurus are positive.
Beware of gurus who make people look and feel wrong, have causes against something rather than for something, and look for punishment rather than compassion.
9. True gurus look content.
This doesn’t mean that a guru may not experience sadness or grief. But seriously, can you imagine a guru who lives in a state of despair, depression, anger or anxiety?
10. True gurus live inside us all.
Many true masters have been their own gurus (the Buddha being just one example). No matter what anyone says, you don’t need ONE guru, because the real guru resides in every one of our hearts.