Hadithcore
Musnad Ahmad, 256
sahih· Darussalam

It was narrated that Subayy bin Ma`bad al-Taghlibi said:

I had recently converted from Christianity and I wanted to go for jihad or for Hajj, I went to a man of my people whose name was Hudaim, and asked him, and he told me to do Hajj, So I did qiran (Hajj and `Umrah together).

حَدَّثَنَا عَبْدُ الرَّزَّاقِ أَنْبَأَنَا سُفْيَانُ عَنْ مَنْصُورٍ عَنْ أَبِي وَائِلٍ عَنْ صُبَيِّ بْنِ مَعْبَدٍ التَّغْلِبِيِّ قَالَ كُنْتُ حَدِيثَ عَهْدٍ بِنَصْرَانِيَّةٍ فَأَرَدْتُ الْجِهَادَ أَوْ الْحَجَّ فَأَتَيْتُ رَجُلًا مِنْ قَوْمِي يُقَالُ لَهُ هُدَيْمٌ فَسَأَلْتُهُ فَأَمَرَنِي بِالْحَجِّ فَقَرَنْتُ بَيْنَ الْحَجِّ وَالْعُمْرَةِ فَذَكَرَهُ‏.

References1 variant
In-Book Reference
Book 2, Hadith 170