He speaks doubtfully, partly because he was uncertain how far God would pardon them, and partly to quicken them to the more serious practice of repentance.
Related Commentaries of Exodus 32:30
Exodus 32:30
30 And it came to pass on the morrow, that Moses said unto the people, Ye have sinned a great sin: and now I will go up unto the LORD; peradventure I shall make an atonement for your sin.