A.T. Robertson Commentary Romans 15:30

"Now I beseech you, brethren, by our Lord Jesus Christ, and by the love of the Spirit, that ye strive together with me in your prayers to God for me;" — Romans 15:30 (ASV)

By (δια). The intermediate agents of the exhortation (the Lord Jesus and the love of the Spirit) as δια is used after παρακαλω in 12:1.

That ye strive together with me (συναγωνισασθα μο). First aorist middle infinitive of συναγων ζομα, old compound verb, only here in N.T., direct object of παρακαλω, and with associative instrumental case μο, the simplex αγωνιζομενος, occurring in Col 4:12 of the prayers of Epaphras. For Christ's agony in prayer see Mt 26:42; Luke 22:44.