This verse is from the Bhagavad Gita, Chapter 6, Verse 31. It is written in Sanskrit and translates to English as follows:
sarva-bhūta-sthitaṁ yo māṁ bhajatyekatvam āsthitaḥ
sarvathā vartamāno ’pi sa yogī mayi vartate || 31 ||
"The ideal qualities of a yogi have been revealed in this verse. Lord Krishna says that the person who knows that I (God) reside equally in every being and worships me while being situated in this feeling of unity, he actually attains the highest level of yoga. Such a yogi, no matter what the situation is, is always situated in me, because there is no thought of discrimination or separation in his mind."
Lord Krishna says that the person who understands that I (God) am situated in all beings, and experiences the feeling of unity in all, he becomes completely situated in me. That is, the person who knows that God is equally present in all beings and worships me with this feeling, he remains situated in me in every situation of life like a true yogi.
sarvabhutasthitam – situated in all beings
yo – one who
ma – me
bhajati – worships, worships, or loves
ektvaamasthita – situated in unity, situated in non-duality
sarvatha – in all ways
vartaman: – one who is situated, who lives
api – bhi
sa – that
yogi – yogi
mayi – in me
vartate – is situated, lives