Warumi 15 : 20 Romans chapter 15 verse 20

kadhalika nikijitahidi kuihubiri Injili, nisihubiri hapo ambapo jina la Kristo limekwisha kutajwa, nisije nikajenga juu ya msingi wa mtu mwingine;
soma Mlango wa 15

yes, making it my aim to preach the Gospel, not where Christ was already named, that I might not build on another's foundation.