I take the example from the bamboo acrobat simile and apply it to friendships.
And how do you look after others by looking after yourself? By development, cultivation, and practice of meditation. And how do you look after yourself by looking after others? By acceptance, harmlessness, love, and sympathy.
Thinking ‘I’ll look after myself,’ you should cultivate mindfulness meditation. Thinking ‘I’ll look after others,’ you should cultivate mindfulness meditation. Looking after yourself, you look after others; and looking after others, you look after yourself.
So if I am looking after myself–by following Buddhist practices to reach awakening–then I should be with someone who also looks after themselves and therefore can help me cultivate wholesome states. I don’t think that this necessarily means they have to be Buddhist even, the qualifications on who to keep around and who to avoid, their a whole list of things and ways to cultivate good qualities in MN 114 since it is shortened by ellipse I’ll put a copy from AN 9.6 on association here,
When I associate with this person, unskillful qualities decline, and skillful qualities grow.
The people who keep you company therefore should show you compassion and allow skillful qualities that lead to stream-entry to grow and the unskillful qualities to decline. The support of friends is very important in our lives, if you’re in social isolation you can probably tell that by now! That means their attainments aren’t as important as much as the qualities that they promote in you, this can also be found in the Sigalaka Sutta (DN 31).
You’re allowed to be an island unto yourself in Buddhism, so it’s not necessary to make sure you’re on the same page in every respect. I think that you can even be on different books as long as the material is similar and you’re cultivating qualities praised by the Buddha. You can see this in AN 7.62 where the Buddha praises good deeds, and AN 4.125 where the Buddha talks about the benefits of metta/brahmaviharas. But the key difference between the Buddha’s teachings and the results of generating pure metta is that it leads to weakening or removing greed, hatred, and delusion. The problem with pure metta is that once their good kamma runs out they are no longer able to stay in heavenly realms and will slide back down but those who understand the dhamma stay there until they reach awakening, all of this is explained in SN 46.54, Full of Love.
Look after yourself and your own actions cultivating what you know to be good, and associate with people who encourage you to keep doing good things and avoid doing bad things. Even if they don’t understand the dhamma, it’ll still help you along the path as long as you are determined enough to be an island of Buddhist understanding–dukkha, annica, anatta-- supported by those who are cultivating brahmaviharas. (People with strong faith in God can be amazingly strong at growing metta!)