Mark 12:28-29

Then one of the scribes [an expert in Mosaic Law] came up and listened to them arguing [with one another], and noticing that Jesus answered them well, asked Him, “Which commandment is first and most important of all?” [Matt 22:34-40; Luke 10:25-28] Jesus answered, “The first and most important one is: ‘HEAR, O ISRAEL, THE LORD OUR GOD IS ONE LORD