Not everyone liked Paul! Well, I guess that’s to be expected. Not everyone liked Jesus! There will always be those who don’t like us, regardless of our efforts. Even in church! There were people in just about every church 
that Paul planted that rose up to contest Paul’s teachings and character. Sometimes the animosity became so great that Paul’s opponents were motivated to do what he did, preach the Gospel, out of jealousy and envy. They even wished Paul harm! But Paul didn’t care! He didn’t strike back. He actually said that he was glad and that he “rejoiced” that they were preaching the gospel even if from wrong motives. He felt that way because there were still many who loved him and partnered with him and supported him and cared for him. These are the people that Paul was talking about in verse 15 were those who preached the gospel from a motive of goodwill. Philippians 1:16 he says that his supporters who preach the gospel “do it out of love, knowing that I am put here for the defense of the gospel.”
Love is the purest of all motives. Jesus taught us that there is nothing more important in our lives than to love God and to love others. Love, in the Biblical sense (Agape) is not a feeling. It’s self-sacrificial living. It’s what moved God to send His Son. John 3:16 teaches us that “God so loved…that he gave His only Son.” Love is a divine motive. Doing something good like preaching the Gospel from wrong motives is still doing good. Yet, doing good from wrong motives is not enough to make someone a good person. God wants us to be people who do good from good motives. It’s totally possible to give without loving, but it’s impossible to love without giving. The wrong motive doesn’t always guarantee wrong actions but the right motive always guarantees the right actions. One philosopher said, “Motives cannot be isolated from deeds. For instance, the motive of love is necessarily connected with the objective deeds of benevolence, not murder or rape.”
God deals with our motives! Motives are more important to God than our actions. Paul defends his behavior with the Thessalonians and says in 1 Thessalonians 2:4, “Our purpose is to please God, not people. He alone examines the motives of our hearts.” God cares more about what’s in our hearts. But God is the only one who really knows. When under criticism from others in Corinth Paul defends himself by saying, “I call God as my witness—he knows my heart!” (See 2 Corinthians 1:23). Jesus also taught us that murder and adultery are not just actions. They are conditions of our heart. He says that to hate is the same as murder. He says to lust is the same as adultery. Motives, or our hearts, really matter to God. That’s why Proverbs 4:23 tells us “Above everything else, guard your heart. It is where your life comes from.”