As far as "Yogavāsiṣṭha" VI.126.4 (= "Laghuyogavāsiṣṭha" VI.15.14) is concerned, the following publication is of essential importance:

Jürgen Hanneder: "Dreams and other States of Consciousness in the Mokṣopāya". In: Claudine Bautze-Picron (Ed.): The Indian Night. Sleep and Dream in Indian Culture“. Delhi 2009, pp. 65–99.

Best,
Roland Steiner

> Also in the work called Yogavāsiṣṭha,
>
> 17.    Just like the head of a struggling turtle
>          finally surfaces into a calm
>          in the midst of  innumerable turbulent waves,
>          so a person finally becomes discerning after many births.
>
> (Cover, Jennifer and Grahame (2014). Bodhasara The surprise of awareness, Createspace, USA, p174-175
> (Narahari (1905). Bodhasāra (with a commentary by Divākara), Benares Sanskrit series. Benares: Chowkhamba
> Sanskrit Book Depot, p223)
>
> F/N (Cover p175-176)
> Yogavāsiṣṭha (Nirvāṇaprakaraṇam Book 6.1 Section 126, verse 4)
> (Yogavāsiṣṭha of Vālmīki 1984:1050) and Laghu Yogavāsiṣṭha
> (Laghu-Yogavāsiṣṭha 6.15.14). The sense here is that it is extremely difficult to become discerning. There are seven
> steps of knowledge, but even to begin on the first step takes effort, and possibly many births. The difficulty of a
> struggling turtle finally surfacing into a calm in the midst of  innumerable turbulent waves, is a clear metaphor for the
> level of difficulty.