Is the statement by Ibn Abbas, "Whoever prays two rak'ahs after Isha will spend the night prostrating and standing," a sound hadith that can be acted upon, and are these two rak'ahs other than the Sunnah of Isha, and the Shaf' and Witr?

This narration from Ibn Abbas, regarding the interpretation of the verse "And those who spend the night in adoration of their Lord prostrating and standing," states that whoever prays two or more rak'ahs after Isha has spent the night prostrating and standing for Allah. However, there is no verifiable chain of narration for this statement to ascertain its authenticity. Ibn Abbas's intention is that the essence of night prayer is achieved by whoever prays two rak'ahs or more, and whoever adds more, it is better. Night prayer is among the best acts of closeness to Allah, and some exegetes view the verse as praising those who revive the night or most of it with prayer.