Evidently there were some widows whose behavior was not in keeping with the gospel, bringing reproach upon the Church (cf. 1 Tim. 3:7; 6:1; Tit. 2:5, 8). While not all widows would engage in unchristian conduct, some may.
The phrase "saying things they ought not to" may refer to false teachings (cf. 1 Tim. 5:15; 1:3; 4:7) or simply to gossip and improper intrusion into the lives of others ("house to house" meaning circuit of the houses; cf. Acts 19:13; 28:13). Instead of this ungodly, sinful conduct, younger widows should marry, have children (cf. 1 Tim. 2:15), and properly manage their homes.
Paul gave a lot of attention to widows, perhaps because some of the younger widows had come under the influence of the false teachers (2 Tim. 3:6-7) or been enticed by sensual desires to abandon the faith (1 Tim. 5:11-12). Lea remarks:
It was urgent for Paul to speak and for the younger widows to respond. Some who had pledged a commitment to widowhood were not living as the true widow of 1 Tim. 5:5, 9-10. They had abandoned their trust in God and had become involved in gossip, false teaching, strife, and discord within the church (1 Tim. 5:15).
In 1 Timothy 5:16 Paul urges "any woman who is a believer [having] widows in her family" to use her time, wealth, or both to care for the needy widows. Kistemaker states:
Needy widows are first of all the responsibility of those who are nearest to them; for example, children, grandchildren, women of means who stand in a relation of closeness to them. Let them then do their duty. Not only is this morally the right thing to do, but there is also a very practical consideration. The church has its hands full as it is. It does not count many rich people among its members (Mark 10:25; cf. 1 Cor. 1:26). Hence, it should not be burdened (weighed down with too heavy a load; for the verb see also 2 Cor. 1:8; 5:4; then Matt. 26:43; Luke 9:32; 21:34). Without this extra burden it will be able to assist "those who are really (what is implied in the name) widows." . . . These are the widows who are completely destitute, having no one to support them. If everyone does his part, it will be so much easier for the church to care for these widows. Truly, a lesson also for today!
give no opportunity for the enemy to slander us. Paul understands the church as a unity. Those who are vulnerable need support not only for their own sake but also for the sake of the whole community. Each part of the household must work for the sake of others, because Satan, whose name means 'adversary,' always opposes God's people. At Ephesus, 'some' in the church have 'turned aside' and joined the opposition.