Neither cold nor hot. — The “heat” here is the glowing, fervent zeal and devotion which is commended and commanded elsewhere (Romans 12:11). It is not, however, the self-conscious, galvanised earnestness which, in days of senile pietism, passes for zeal. It is an earnestness which does not know itself earnest, being all too absorbed in its work. It is self-forgetful, and so self-sacrificing, rather than ambitious of self-sacrifice. It is, in short, kindled of God, and sustained by
converse with the Divine One (Luke 24:32), and restored by intercourse with Him (see Revelation 3:20; comp. 1 John 4:15-20). The “cold” describes the state of those who are as yet untouched by the Gospel of Love. An intermediate state between these is the “lukewarm”; such are neither earnest for God nor utterly indifferent to religion. They are, perhaps, best described as those who take an interest in religion, but whose worship of their idol of good taste, or good form, leads them to regard enthusiasm as ill-bred, and disturbing; and who have never put themselves to any inconvenience, braved any reproach, or abandoned any comfort for Christ's sake, but hoped to keep well with the world, while they flattered themselves that they stood well with God; who were in danger of betraying their Master, Judas-like, with a kiss. With the denunciation of “lukewarmness” here we may compare the exhortation to greater ministerial earnestness addressed to Archippus (Colossians 4:17).
I would.... — The wish is not that they might grow cold rather than remain in this lukewarm state, it is more a regret that they are among those who are in a condition which is so liable to self-deception; such a state is “both to God displeasing and to His foes.” And this is expressed in startling language, “I am about (such is the force of the words) to spue thee....”