وَاسْتَغْفِرْهُ
And seek His forgiveness. (110:3)
Istaghfir is an imperative joined by wāw to the preceding sabbiḥ. The pronoun -hu refers to Allah, made clear by rabbika and the earlier naṣr Allāh. Thus two related acts — praise and glorification, and seeking forgiveness — form one connected response.
Wāw coordinates the commands; it does not by itself prove a fixed temporal order. The earlier fāʾ linked the whole response to its condition, whereas wāw adds another directive within that response.