It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that he said: "I have heard the (various) readings, and I found them close to one another (in meaning and sense). So recite as you have been taught, and beware of going to extremes (in matters of the Qur'an), hair-splitting and disagreement, for these (various readings) are just like one of you saying 'halumma' (come here) and 'ta'al' (come) (that is, both mean the same thing)."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Hamzah (may Allah have mercy on him) except Ishaq (may Allah have mercy on him)."
Hadith Referenceالمعجم الأوسط / باب الألف / 1409
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» برقم: 34، والبيهقي فى «السنن الكبرى» برقم: 4060، وابن أبي شيبة فى «مصنفه» برقم: 30651، والطبراني فى «الكبير» برقم: 8680»