Albert Barnes Commentary Matthew 22:37

"And he said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind." — Matthew 22:37 (ASV)

Jesus said to him, etc. Mark says that he introduced this by referring to the doctrine of the unity of God—Hear, O Israel; the Lord our God is one Lord—taken from Deuteronomy 6:4. This was said, probably, because all true obedience depends on the correct knowledge of God. No one can keep His commandments who is not acquainted with His nature, His perfections, and His right to command.

You shall love the Lord your God, etc. The meaning of this is, you shall love Him with all your faculties or powers. You shall love Him supremely, more than all other beings and things, and with all the ardour possible. To love Him with all the heart is to fix the affections supremely on Him, more strongly than on anything else, and to be willing to give up all that we hold dear at His command.

With all your soul. Or, with all your life. This means, to be willing to give up the life to Him, and to devote it all to His service; to live to Him, and to be willing to die at His command.

With all your mind. This means to submit the intellect to His will; to love His law and gospel more than you do the decisions of your own minds; to be willing to submit all your faculties to His teaching and guidance; and to devote to Him all your intellectual attainments and all the results of your intellectual efforts.

With all your strength, (Mark). This means with all the faculties of soul and body; to labour and toil for His glory, and to make that the great object of all your efforts.