Is Paul making salvation (reaping of the harvest) conditional on our obedience by saying "if we do not give up"?
Paul wants to encourage Christian believers to persevere in doing good and not to give up. In this, he is not claiming that our works contribute to our salvation, but rather affirming that good works will be evident in the lives of those who belong to Jesus Christ. 1 The power and desire to persevere in doing good is one that comes from the Holy Spirit. 2
9 Ne nous lassons pas de faire le bien; car nous moissonnerons au temps convenable, si nous ne nous relâchons pas.