﴿ ثُمَّ أَفِيضُوا۟ مِنْ حَيْثُ أَفَاضَ ٱلنَّاسُ وَٱسْتَغْفِرُوا۟ ٱللَّهَ ۚ إِنَّ ٱللَّهَ غَفُورٌۭ رَّحِيمٌۭ ﴾

“and surge onward together with the multitude of all the other people who surge onward, and ask God to forgive you your sins: for, verily, God is much-forgiving, a dispenser of grace.”

Then thumma denotes the sequence intended press on O Quraysh from where the people press on that is from ‘Arafa by standing there together with them for they used to stand at Muzdalifa disdaining to stand with other people; and seek God’s forgiveness for your sins; God is Forgiving Merciful to the believers.