Likewise, when Peter exhorts, ‘love one another from the heart fervently,’ (1 Peter 1:22) the implication is that not all human love reaches those heights.

‘ . . . the love of many will grow cold,’ says Matthew 24:12. The use of the verb, here translated ‘grow cold,’ implies a process of getting colder rather than instant coldness, and Revelation 3:15-16 refers to Christians who are neither hot nor cold but lukewarm.

Paul’s prayer is that the Philippians’ “love may abound yet more and more in knowledge and all discernment,” (Philippians 1:9).

Note what he says here:

2 Thessalonians 1:3  . . . your faith grows exceedingly, and the love of each and every one of you toward one another abounds

Many versions (19 Examples) make the meaning of ‘abounds’ clearer by translating it ‘increasing.’ Others speak of love growing (Easy-to-Read Version, International Children’s Bible, New Living Translation, Orthodox Jewish Bible). ‘Grows ever greater’ is how the New American Standard Bible puts it. ‘Growing all the time,’ says the Contemporary English Version. ‘Becoming greater,’ says the Good News Translation, while the New English Translation says, ‘is ever greater,’ and ‘stronger all the time’ is the New Life Version's rendering. The New Testament for Everyone says ‘multiplying,’ and the Worldwide English (New Testament) says, ‘You all love each other more and more.’

These verses are similar:

1 Thessalonians 3:12 and the Lord make you to increase and abound in love one toward another, and toward all men . . .

1 Thessalonians 4:9-10 But concerning brotherly love, you have no need that one write to you. For you yourselves are taught by God to love one another, for indeed you do it toward all the brothers who are in all Macedonia. But we exhort you, brothers, that you abound more and more