For there are different reasons why men cannot marry: some, because they were born that way; others, because men made them that way; and others do not marry for the sake of the Kingdom of heaven. Let him who can accept this teaching do so.”
(Matthew 19:12)

Paul encouraging the unmarried or widows to remain unmarried as God's perfect-will in their lives but instead of pretending to be unmarried for the sake of faith in Jesus Christ Crucified yet living in sexual-lust let them marry or re-marry for widows/widowers thus

"For I wish that all men were even as I myself(unmarried). But each one has his own gift from God, one in this manner and another in that.
8 But I say to the unmarried and to the widows: It is good for them if they remain even as I am; 9 but if they cannot exercise self-control, let them marry. For it is better to marry than to burn with passion." (1 Cor. 7:8-9)


"A wife is bound by law as long as her husband lives; but if her husband dies, she is at liberty to be married to whom she wishes, only in the Lord. 40 But she is happier if she remains as she is, according to my judgment—and I think I also have the Spirit of God." (1 Cor. 7:39-40)

"Therefore I desire that the younger widows marry, bear children, manage the house, give no opportunity to the adversary to speak reproachfully. 15 For some have already turned aside after Satan." (1 Timothy 5:14-15)