In reading several commentaries, I keep seeing James 1.27 referred back to Isaiah 1.15-16. Admittedly, because I don’t have the time to search my entire library, I cannot tell you no one else has connected James 1.27 to Sirach 4.10. (Briefly looking at commentaries on Sirch, some have made allusions between the two.)
Read all of Sirach 4 here.
Sirach 4.10 reads,
Be like a father to orphans,
and take the place of a husband to widows.
Then God will call you his child,
and he will be merciful to you and deliver you from the pit.
James 1.27 reads,
Religion that God our Father accepts as pure and faultless is this: to look after orphans and widows in their distress and to keep oneself from being polluted by the world.
You can easily see the connection. Not merely with the use of orphans and widows, but so too to the allusion of cleansing from sin.
Now, I’m not going to compare the rest of James 1 to Sirach 4, but you can.
This is important for several reasons. One, it informs James’s reception as part of the Wisdom tradition. This is really beyond doubt, in my opinion. Of course, in doing so, I am left to wonder how close a Jacobite Christology is to the Wisdom theology found in Sirach (Say, Sirach 24). Anyway, I would encourage you to read Sirach sometime.