Verses with the word slack in the Apocrypha (6 verses):

2 Esdras 16:37
Behold, the plagues draw nigh, and are not slack.

2 Esdras 16:38
As when a woman with child in the ninth month bringeth forth her son, with two or three hours of her birth great pains compass her womb, which pains, when the child cometh forth, they slack not a moment:

2 Esdras 16:39
Even so shall not the plagues be slack to come upon the earth, and the world shall mourn, and sorrows shall come upon it on every side.

Tobit 12:6
Then he took them both apart, and said unto them, Bless God, praise him, and magnify him, and praise him for the things which he hath done unto you in the sight of all that live. It is good to praise God, and exalt his name, and honourably to shew forth the works of God; therefore be not slack to praise him.

Sirach 4:29
Be not hasty in thy tongue, and in thy deeds slack and remiss.

Sirach 35:18
For the Lord will not be slack, neither will the Mighty be patient toward them, till he have smitten in sunder the loins of the unmerciful, and repayed vengeance to the heathen; till he have taken away the multitude of the proud, and broken the sceptre of the unrighteous;