Jamieson, Fausset and Brown on Luke 9:61

61. I will follow ... but--The second disciple had a "but" too--a difficulty in the way just then. Yet the different treatment of the two cases shows how different was the spirit of the two, and to that our Lord addressed Himself. The case of Elisha (1Ki 19:19-21), though apparently similar to this, will be found quite different from the "looking back" of this case, the best illustration of which is that of those Hindu converts of our day who, when once persuaded to leave their spiritual fathers in order to "bid them farewell which are at home at their house," very rarely return to them. (Also see on Mt 8:21.)