Deuteronomy 16:16,17

"Three times a year all your men must appear before the Lord your God at the place he will choose: at the Feast of Unleavened Bread, the Feast of Weeks and the Feast of Tabernacles. No man should appear before the Lord empty-handed:  Each of you must bring a gift in proportion to the way the Lord your God has blessed you."

{Deuteronomy 16:16,17}  (NIV1984)

Here is the stipulation of the old covenant. Each of us is to appear before the LORD 3 times a year. We must travel to the place where the Ark of the Covenant (the manifest Presence of God). We must bring a gift for the LORD relative to His material blessing in our lives. 

Compare this to the new covenant we have in Christ. 

We are to pray continually, and daily acknowledge that He is near us (Phil 4:4-6). His manifest Presence is within us and travels where ever we go (1 Cor 6:19). We are to offer our lives as a daily gift to Him (Rom 12:2).  

These comparisons are all a blessing! But this last one is tremendous! They must appear with something in their hands. We must appear empty-handed. Blessed are the poor in spirit; for theirs is the kingdom of heaven. Our Lord brought all that God required. We have nothing to offer, except empty hands. If we bring anything to Him, except in thanksgiving, we fall away from grace (Gal 5:4). 

The words of the old hymn Rock of Ages speak to this tremendous truth, about the grace of God in our lives.  

Nothing in my hand I bring. Simply to the cross I cling.
Naked, come to Thee for dress; Helpless look to Thee for grace;
Foul, I to the fountain fly; Wash me, Savior, or I die. 

 {"Rock of Ages", Text: Augustus M. Toplady, 1740-1778,
Music: Thomas Hastings, 1784-1872}