something like this should work:
Sub formarr()
Dim inarr As Variant
With Worksheets("Sheet2")
lastrow = .Cells(Rows.Count, "A").End(xlUp).Row
inarr = Range(.Cells(1, 1), .Cells(lastrow, 6))
End With
With Worksheets("Sheet1")
lastrow1 = .Cells(Rows.Count, "A").End(xlUp).Row
thisarr = Range(.Cells(1, 1), .Cells(lastrow1, 6))
End With
For i = 1 To lastrow1
For j = 1 To lastrow
If thisarr(i, 1) = inarr(j, 1) And thisarr(i, 1) <> "" Then
With Cells(i, 2)
.FormatConditions.AddIconSetCondition
.FormatConditions(1).SetFirstPriority
With .FormatConditions(1)
.ReverseOrder = False
.ShowIconOnly = False
.IconSet = ActiveWorkbook.IconSets(xl3Arrows)
End With
With .FormatConditions(1).IconCriteria(2)
.Type = xlConditionValueNumber
.Value = 0
.Operator = 7
End With
With .FormatConditions(1).IconCriteria(3)
.Type = xlConditionValueNumber
.Value = inarr(j, 4)
.Operator = 7
End With
End With
End If
Next j
Next i
End Sub