The weighing on that day is the true (weighing). As for those whose scale is heavy, they are the successful.

Quran

Surat Al-'A`rāf (The Heights) - سورة الأعراف  7:8

tafsir:

 And the weighing on that Day will be the true (weighing). So, as for those whose scale (of good deeds) will be heavy, they will be the successful (by entering Paradise).