Philippians 4:13
“I can do all things through him who strengthens me.”
Context around the verse (verse 11 is key)
Philippians 4:10-13
I rejoiced in the Lord greatly that now at length you have revived your concern for me. You were indeed concerned for me, but you had no opportunity. Not that I am speaking of being in need, for I have learned in whatever situation I am to be content. I know how to be brought low, and I know how to abound. In any and every circumstance, I have learned the secret of facing plenty and hunger, abundance and need. I can do all things through him who strengthens me.
Background of the letter (Paul is in prison)
Philippians 1:12-14
I want you to know, brothers, that what has happened to me has really served to advance the gospel, so that it has become known throughout the whole imperial guard and to all the rest that my imprisonment is for Christ. And most of the brothers, having become confident in the Lord by my imprisonment, are much more bold to speak the word without fear.
Knowing that everything Paul has gone through that put him in these situations was because he chose to follow Christ. The key to this verse is the power of Christ helping us persevere and endure after we have made decisions to please God and not for selfish ambitions. This stems from living out the gospel and sharing it with others. This verse is not saying if I take a test to get a job to make more money I can do it through the power of Christ. Now the power of the Holy Spirit can help us do life better but the goal is to bring our Heavenly Father glory not ourselves.