We cannot give out to others what we do not have. For example, when we have no money, can we give money to others? When we have nothing to eat, can we give anything to others so that they can eat and be satisfied? We can give only what we have.
Spiritually, it is the same. We cannot give what is not in us. When there is no love in us, can we share love to others? When we have no patience, can we be patient to others? When we have no mercy in us, can we show mercy to others? We cannot. We can give only what is in us.
For this reason, Paul emptied out from inside what belonged to him, and he filled himself with Christ.
Galatians 2:20 I have been crucified with Christ and I no longer live, but Christ lives in me.
Since Christ lived in him, he could live the life Christ gave as example. It is the same with us. We also must crucify ourselves and fill ourselves with Christ: love, compassion, kindness, humility, gentleness, patience, etc.. God is holy and God wants us to be holy like Him. We should resemble God in every way. Then we can give to others good things stored in us.