Paul says “Rejoice in hope, be patient in tribulation, be constant in prayer.” Those 11 words summarise our lives completely. No matter what happens to us, the ideas contained in those 11 words apply.
Of course, there are other things we should do as we strive to follow the example of Jesus. Paul describes some of them too. “Do not be conformed to this world”; “Love one another with brotherly affection”; “Bless those who persecute you”; “Rejoice with those who rejoice, weep with those who weep”.
So Romans 12 is essentially a roadmap for our life as Christians, neatly summarising the attitudes and principles involved.
David describes the essentials of life in a different way, but the principles are much the same.
“Hear my cry, O God, listen to my prayer; from the end of the earth I call to you when my heart is faint. Lead me to the rock that is higher than I, for you have been my refuge, a strong tower against the enemy…So will I ever sing praises to your name, as I perform my vows day after day.”