The command we are given in this passage is to draw near to God. The great aim of the writer of the book of Hebrews is that we get near God, that we have fellowship with him, that we not settle for a Christian life at a distance from God.
This drawing near is not a physical act. It's not building a tower of Babel by your achievements to get to heaven. It's not necessarily going to a church building. Or walking to an altar at the front. It is an invisible act of the heart. You can do it while standing absolutely still, or while lying in a hospital bed, or on 52 as you commute to work.
This is the center of the gospel-that God has done astonishing and costly things to draw us near to himself. He has sent his Son to suffer and to die so that through him we might draw near. Everything that He has one in the great plan of redemption is so that we might draw near. And that nearness is for our joy and for His glory.
He does not need us. If we stay away He is not impoverished. He does not need us in order to be happy in the fellowship of the Trinity. But He magnifies His mercy by giving us free access through His Son, in spite of our sin, to the one Reality that can satisfy our souls completely and forever; namely, himself. "In your presence there is fullness of joy; at your right hand are pleasures forevermore" (Psalm 16:11).
This is God's will for you, even as you read this. This is why Christ died: that you would draw near to God.