"We who are strong have an obligation to bear with the failings of the weak, and not to please ourselves. Let each of us please his neighbor for his good, to build him up. For Christ did not please himself, but as it is written, 'The reproaches of those who reproached you fell on me.' For whatever was written in former days was written for our instruction, that through endurance and through the encouragement of the Scriptures we might have hope." - Romans 15:1-4 ESV
In this case Paul numbers himself among the strong. Strong in what? Was he a strong business man? Did he have physical stamina and skill? It seems he had all of those things. But it was the strength of a spiritual life that he references when he references Christ's work. The strength of forgiveness. The insight into the grace of God.
"May the God of endurance and encouragement grant you to live in such harmony with one another, in accord with Christ Jesus, that together you may with one voice glorify the God and Father of our Lord Jesus Christ. Therefore welcome one another as Christ has welcomed you, for the glory of God. For I tell you that Christ became a servant to the circumcised to show God's truthfulness, in order to confirm the promises given to the patriarchs, and in order that the Gentiles might glorify God for his mercy. As it is written, 'Therefore I will praise you among the Gentiles, and sing to your name.' " - Romans 15:5-9 ESV
The strength of the vertical contributes to strength in the horizontal life. Jesus had 'inreach' so that He could have 'outreach'.
"And again it is said,
'Rejoice, O Gentiles, with his people.'
'Praise the Lord, all you Gentiles, and let all the peoples extol him.'
And again Isaiah says,
'The root of Jesse will come, even he who arises to rule the Gentiles; in him will the Gentiles hope.'
May the God of hope fill you with all joy and peace in believing, so that by the power of the Holy Spirit you may abound in hope.' - Romans 15:10-13 ESV
Our God is the God of endurance, encouragement and hope. The weakest of us can have strength flowing from that. We can 'give' what can only flow from Jesus... eternal forgiveness, mercy, divine favor... to those we know and then from that base of operations we can reach the world around us.
Today we are islands of strength... not because of what we can do... but because of the grace and mercy that has been given to us and the knowledge of God's character and nature.
"For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. For God sent not his Son into the world to condemn the world; but that the world through him might be saved." - John 3:16-17 KJV