“Now may the God who supplies endurance and comfort grant you to have among yourselves the same mental attitude that Christ Jesus had.”
~Romans 15:5

Paul had just advised Christians who were strong in the faith to selflessly bear the weaknesses of others. (Rom 15:1-3)
This requires a lot of humility and is not an easy thing to nurture in ourselves.
Being imperfect, we tend towards selfishness. (Eccl. 7:20; Rom. 7:18,19; 12:16)
Every day we have to struggle against the negative, discontent, self-centered spirit in the world. (Eph. 2:2; 4:17,18)
We may relate to the following statement: “Our obvious imperfection, standing in sharp contrast with the perfect pattern that Jesus left us, may at times cause us to be discouraged. We may doubt that having the same mental attitude that Jesus had is even possible.”
Despite our inability to carry out everything God requires of us, we can still serve him in a way that pleases him.
We can read about dozens of exemplary people in the Bible who managed to serve him faithfully and be inspired to imitate their humble attitudes.(Rom. 15:4)