To set the mind on the flesh is death, but to set the mind on the Spirit is life and peace. For this reason the mind that is set on the flesh is hostile to God; it does not submit to God’s law—indeed it cannot, and those who are in the flesh cannot please God. But you are not in the flesh; you are in the Spirit, since the Spirit of God dwells in you. Anyone who does not have the Spirit of Christ does not belong to him. But if Christ is in you, though the body is dead because of sin, the Spirit is life because of righteousness. If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ from the dead will give life to your mortal bodies also through his Spirit that dwells in you. (Romans 8:6-11, NRSV)
If we focus on our flesh, on our own self-gratifications, we will not be filled with life because we will not be connected to Christ.
Christ came to show us that we need to die to self and to look to the other. That was His life, living for the other. He lived for you.
So if you are focused on you, He is not in you. But if you are focused on the other, then you are living in the Spirit.
So look out for the other and live the life of the Spirit, the life of Christ.