Just wondering what consists of a "spiritual friend" & a friend worthy of associated in Buddhism ?
Spiritual friendship... can be someone on the same spiritual path as you and offer support and companionship on the path to Buddhahood.
An excerpt from Sigolavada Sutta on 'worthy friends':
http://www.accesstoinsight.org/tipitaka/dn/dn.31.0.nara.html
"These four, young householder, should be understood as warm-hearted friends:
(1) he who is a helpmate,
(2) he who is the same in happiness and sorrow,
(3) he who gives good counsel,
(4) he who sympathises.
(1) "In four ways, young householder, should a helpmate be understood as a warm-hearted friend:
(i) he guards the heedless,
(ii) he protects the wealth of the heedless,
(iii) he becomes a refuge when you are in danger,
(iv) when there are commitments he provides you with double the
supply needed.
(2) "In four ways, young householder, should one who is the same in happiness and sorrow be understood as a warm-hearted friend:
(i) he reveals his secrets,
(ii) he conceals one's own secrets,
(iii) in misfortune he does not forsake one,
(iv) his life even he sacrifices for one's sake.
(3) "In four ways, young householder, should one who gives good counsel be understood as a warm-hearted friend:
(i) he restrains one from doing evil,
(ii) he encourages one to do good,
(iii) he informs one of what is unknown to oneself,
(iv) he points out the path to heaven.
(4) "In four ways, young householder, should one who sympathises be understood as a warm-hearted friend:
(i) he does not rejoice in one's misfortune,
(ii) he rejoices in one's prosperity,
(iii) he restrains others speaking ill of oneself,
(iv) he praises those who speak well of oneself."
Thus spoke the Exalted One. And when the Master had thus spoken, he spoke yet again:
The friend who is a helpmate,
the friend in happiness and woe,
the friend who gives good counsel,
the friend who sympathises too —
these four as friends the wise behold
and cherish them devotedly
as does a mother her own child.
The wise and virtuous shine like a blazing fire.
He who acquires his wealth in harmless ways
like to a bee that honey gathers,6
riches mount up for him
like ant hill's rapid growth.
With wealth acquired this way,
a layman fit for household life,
in portions four divides his wealth:
thus will he friendship win.
One portion for his wants he uses,7
two portions on his business spends,
the fourth for times of need he keeps.