For he is our God - Not only the God whom we worship as the true God, but One who has revealed himself to us as our God. We worship him as God - as entitled to praise and adoration because he is the true God; we worship him also as sustaining the relation of God to us, or because we recognize him as our God, and because he has manifested himself as ours.
And we are the people of his pasture - whom he has recognized as his flock; to whom he sustains the relation of shepherd; who feeds and protects us as the shepherd does his flock. See the notes at Psalms 79:13; compare Psalms 23:1-3.
And the sheep of his hand - The flock that is guided and fed by his hand.
To day if ye will hear his voice - His voice calling you; commanding you; inviting you; encouraging you. See this passage explained in the notes at Hebrews 3:7-11. The word “today” here means “the present time;” now. The idea is, that the purpose to obey should not be deferred until tomorrow; should not be put off to the future. The commands of God should be obeyed at once; the purpose should be executed immediately. All God’s commands relate to the present. He gives us none for the future; and a true purpose to obey God exists only where there is a willingness to obey “now,” “today;” and can exist only then. A purpose to repent at some future time, to give up the world at some future time, to embrace the Gospel at some future time, is “no obedience,” for there is no such command addressed to us. A resolution to put off repentance and faith, to defer attention to religion until some future time, is real disobedience - and often the worst form of disobedience - for it is directly in the face of the command of God. “If ye will hear.” That is, If there is a disposition or willingness to obey his voice at all; or, to listen to his commands. See the notes at Hebrews 3:7.