Yogasutra Vibhutipada sutra 7-8
Sri Sadgurubhyoh namah
7. trayam antar angam purvebhyah
Meaning: The three (dharana, dhyana, samadhi) will become more of internal activity than external activity and enter into field of mind, and they are different from the other limbs of yoga described before dharana like 'yama, niyama, etc'
8. tad api bahir angam nirbijasya
Meaning: But still external compared to Nirbija samadhi. The three (dharana, dhyana, samadhi) is considered internal when compared to other limbs of yoga, but they are still considered external yoga abhyasa when compared to the final thing called 'Nirbija samadhi' .
Hari OM