The 95th psalm is a prophecy of Christ; the Letter to the Hebrews extensively treats it as a prophecy of the time of the New Testament and of the voice of the Gospel. In short, the psalm teaches and calls us to Christ and to the Word of God, to true worship. The psalmist warns us by the example of the faithless fathers in the wilderness, who also did not come into the promised land on account of their unbelief and contempt for God.
You must, however, apply the entire psalm to Christ: He is Himself the God whom we are exhorted to worship. He has made us and is our shepherd, and we are His sheep. He is the one who tested the unbelieving father, as Paul in 1 Corinthians 10:9 also states. From henceforth He will receive no Mosaic worship, but instead faith, joyful preaching, praise and thanksgiving.
Lord Jesus, teach us to profit by the warning examples of others. So govern us that we do not harden our hearts, as did those at Meribah. Incline our hearts to Your Gospel and enable us by Your good Spirit to receive with meekness the engrafted Word that is able to save the soul. Suffer us not, O Lord, to fall from You, neither in life nor in death. Amen.
(from Reading the Psalms with Luther, pgs. 226-227)