We must not tempt the Lord [that is, test His patience, question His purpose or exploit His goodness], as some of them did—and they were killed by serpents.

Saw

Surely all the men who have seen My glory and My [miraculous] signs which I performed in Egypt and in the wilderness, yet have put Me to the test these ten times and have not listened to My voice,

Then He began to denounce [the people in] the cities in which most of His miracles were done, because they did not repent [and change their hearts and lives].

If I had not done among them the works (attesting miracles) which no one else [ever] did, they would not have [the guilt of their] sin; but now [the fact is that] they have both seen [these works] and have hated Me [and continue to hate Me] and My Father as well.

General references

Yet they still continued to sin against Him
By rebelling against the Most High in the desert.