And undoubtedly, he is himself a witness over it.
He bears witness to this fact
To this he himself shall bear witness
And surely he is a witness of that
And he truly (is) on that witnessing/testifying (E)
Man’s actions bear witness that…
And indeed he himself is a witness to it
And, surely, he bears witness to it by his conduct
And verily, he is himself a witness to this ingratitude
And he himself bears witness to all this (by his conduct)
And to that fact he bears witness (by his deeds)